Abstracts

1

GENERAL ANALYTICAL METHODS

1.1

Fundamentals, methods, apparatus, reagents, automation, data processing

1.1.1

Fundamentals

New look at analytical data through the gnostical method. T, Paukert, I. Rube~ka and P. Kovanic. The gnosticfcal theory - an axiomatic-deductive procedure - represents a new, powerful approach towards evaluating data files. The application of a gnostical analyser is described which may help in finding outliers, testing the homogeneity of sets of data and classifying individual data. As an example~ its use for ascertaining the recommended values for reference materials is demonstrated by means of homogeneous and heterogeneous sets of data. This approach can be used as an alternative to the statistical characterization of data. - Analyst 118, 145-148 (1993). Czech Geol, Surv., CS-11821 Prague 1 (CS) Problems in method-comparison studies. C. Hartmann, J. SmeyersVerbeke and D.L. Massart. In method comparison studies, where both variables used in the regression are subject to error ordinary least square (OLS) can lead to wrong estimates of the regression coefficients. This results in false conclusions. The error made by applying OLS in method-comparison studies is demonstrated with computer simulations. Several normally and rectangulary distributed data sets were randomly generated considering different measurement ranges and measurement errors. The results from OLS were compared with a regression procedure that takes into account the error in both variables. The results obtained with Mandel's method or principal components are much more reliable. - Analusis 21, i 2 5 132 (1993). Pharm. Inst., Vrije Univ., B-1090 Brussels Efficacy of robust analysis of variance for the interpretation of data from collaborative trials. M. Thompson, B. Mertens, M. Kessler and T. Fearn. The statistics produced with the Analytical Methods Committee (AMC) robust analysis of variance method has been compared with the Harmonized Protocol for the interpretation of data from collaborative trials. Many data sets, representing the extremes of concentration and precision, have been selected from published studies and subjected to the two methods for calculating estimates of the mean and the variances of repeatability and reproducibility. In addition the variabilities of the statistics have been investigated by the bootstrap method. The conclusion is that the AMC robust procedure is considerably more reliable than the Harmonized Protocol. Although the two methods give quite close results generally, the variability of the estimates produced by the Harmonized Protocol is considerably greater because of the masking of outliers. Even the robust method gives estimates that are more variable than expectations based on normal distribution theory. Data ranged from concentration values of 1 0 - 1 0 0 % m/m (crude protein by Kjeldahl) with good precision (RSDR~2%) to those of aflatoxins ( 0 - 1 2 ppb) with poor precisions (RSDR~40%). - Analyst 118, 235-240 (1993). Dept. Chem., Birkbeck Coll., Gordon House, 29 Gordon Square, London, WC1H 0PP (GB) Statistical tools used in the improvement of quality control laboratory performance. M. Ciopec. Possibilities how to improve the quality control laboratory's performances are described by using statistical data obtained with a Gage Repeatability and Reproducibility (R&R) software pack. Two types of experimental data have been used: melt flow rate measurements using extrusion plastometers, and percent of ethylene in polymer measurements using an infrared spectrophotometer. A special strategy has been

designed in each case to minimize the deviation, to improve capability indices, to obtain better values for variability of the measurement process, to minimize equipment and appraiser variation, and to improve reproducibility and repeatability statistical values. - Chemom. IntelI. Lab. Syst. 21, 2 1 - 3 4 (1993). Quality Control Lab., Genesis Poiymers, Marysville, MI 48040 (USA) Standardization of second-order instruments. Yongdong Wang and B.R. Kowalski. A general second-order standardization method is developed for application in two-dimensional methods as GC/MS, LC/UV. This secondorder standarization method proceeds by calculating two banded diagonal transformation matrices, using the responses of a common standard sample, to simultaneously correct for the response channel shift and intensity variations in both dimensions or orders. Different from firstorder standardization, these two transformation matrices must be estimated from a set of simultaneous nonlinear equations via the GaussNewton method. The effects of noise and transformation matrix bandwidth on the standardization performance are studied through computer simulation. When tested with experimental LC/UV data, the proposed standardization method can reduce the variation between two runs from 0.15-0.20 to 0.025-0.03 AU. The design of the standard sample is critical for the parameter estimation and response standardization. - Anal Chem. 65, 1174-1180 (1993). Lab. Chemom., Center Process Anal. Chem., Dept. Chem., Univ. Washington, Seattle, WA 98195 (USA) Determination of equilibrium constants by ehemometric analysis of spectroscopic data. M. Kubista, R, Sj6back and B. Albinsson. Equilibrium constants can be obtained without the knowledge of component spectra by means of a chemometric approach from data of spectroscopic titrations. Titrations can be analyzed even when the titration and points are not reached. The component spectra are determined in the analysis. The analysis is based on a decomposition of the recorded spectra into a product of target and projection matrices using NIPALS. The matrices are then rotated to give the correct concentrations and spectral profiles of the components utilizing the functional form of the equilibrium expression. The output of the analysis is the equilibrium constant and the component spectral profiles. The analysis is highly accurate and can be performed on a standard personal computer. The protolytic constant for the equilibrium between the anionic and dianionic forms of fluorescein in aqueous solution and the dimerization constant of benzoic acid in n-heptane were determined using this method. - Anal. Chem. 65, 994-998 (1993). Dept. Phys. Chem., Chalmers Univ. Techn., S-41296 Gothenburg (S) Validation of sulphide-bearing certified reference samples by primary calibration as applied to X-ray fluorescence. G. Staats and S. Strieder. XRF can be used to generate "true" values for reference samples. This advantage provides the analyst with a really valuable values especially for reference samples. Sulphide-bearing certified reference samples were validated by multi-element wavelength-dispersive XRF based on the SI units kilogram and mole. An oxidizing borate fusion ensured complete oxidation of the test samples and provided for identical physical and chemical conditions for reference and test samples. Matrix effects were successfully overcome by computer-aided generation and production of perfectly adapted multi-element calibration samples. The trueness of the validated results was achieved by the application of pure elements or their compounds having quality assured assays. Detailed and accurate analytical information on certified reference samples are reported. - XRay Spectrom. 22, 132-137 (1993). AG der Dillinger Hfittenwerke, D66763 Dillingen/Saar.

150

1 General analytical methods

Application of apparent content curves to molecular fluorescence. Determination of an analyte in the presence of one interferent. M. Llobat Estell6s, C. Alvarez Alonso and A.R. Mauri Aucejo. The concept of the apparent content curves described by M. Llobat Estell+s et al. in Fres. J. Anal. Chem. 342, 539 (1992) is here adapted to fluorometric analyses of binary mixtures. The use of this mathematical method permits the identification of the nature of the interferent in binary analyte-interferent mixtures. The resolution of binary mixtures is however carried out without using a standard interference solution. The method is applied to the resolution of the binary mixtures fluorescein-acridine and fluorescein-eosin. The results are satisfactory in both cases. - Analusis 21, 201-206 (1993). Dept. Anal. Chem., Univ., E46100 Burjassot, Valencia (E) Factor analysis-spectrophotometry for the simultaneous determination of valence states of metals. Bao-ning Wang, Gui-na Tang and Ka-lin Huang. The study of colour reactions in combination with factor analysis leads to a simple and fast method for the spectrophotometric determination of chemical states of metals in solution. Two Mn+/2-(5-bromo-2 pyridylazo)-5-diethylaminophenol systems for the simultaneous determination of the valence states of Cr and Fe were studied. (1) At pH 4.0, Cr In and Cr w react with the reagent to form stable complexes and a slight difference in the wavelengths of maximum absorption (~m~x)between the two complexes is observed when sodium lauryl sulfate, which also acts as a solubilizing and sensitizing agent, is added, viz., 590 nm for Cr m and 593 nm for Cr vl complexes. (2) In the presence of ethanol, both Fe n and Fem form 1:2 complexes with the reagent at pH 2.5-3.5 and the Zmax of the FeII and Fe lu complexes is at 557 and 592 nm, respectively. In the target transformation factor analysis, the K coefficients calculated from the standard mixtures by classical least-squares analysis and a nonzero intercept added to each wavelength are used as the target vector instead of the pure component standards. - Analyst 118, 205-208 (1993). Changchun Inst. Appl. Chem., Acad. Sinica, Changchun, 130022 (RC) Pyrolysis '92 - 10th International Conference on Fundamental Aspects, Processes and Appfications of Pyrolysis. Hamburg, September 28 October 2, 1992. H.-R. Schulten, R.P. Lattimer and W. Kaminsky. The proceedings of this conference are now published in J. A n a l Appl. Pyrolysis. They are divided in the chapters: Analytical and Instrumental Analysis; Pyrolysis in Geochemistry; Biological Science, Tobacco Research; Technical Pyrolysis; Pyrolysis for Biomass Conversion; and Mechanisms and Kinetics of Pyrolysis Reactions. - J. Anal. Appl. Pyrolysis 25, 1 - 4 1 8 (1993).

1.1.2

Optical and analogous methods

5th Austrian-Hungarian International Conference on Vibrational Spectroscopy. This Conference which was held on July 6 - 8 , 1992 in Linz, Austria, is in the meantime expanded to an European event, which is visited by participants from nearly all European countries. The topics of the 1992 conference were Raman spectroscopy, interpretation of IR-spectra and vibrational spectroscopy applied to inorganic compounds including special problems in the field of mineralogy. A great bunch of different themes were discussed. ] 5 papers of posters and lectures which were presented on this conference are published. - Vibr. Spectrosc. 5, 1 142 (1993). Band resolution techniques and Fourier transform infrared spectra of adsorbed species. C. Lamberti, C. Morterra, S. Bordiga, G. Cerrato and D. Scarano. A home-made deconvolution program (Asymgrad) is tested. Asymgrad is able to perform spectral deconvolutions into up to 13 peaks. The number of peaks, their analytical dependence and their symmetry can be defined by the user. The application of this software to some IR spectra of adsorbed species is presented. - Vibr. Spectrosc. 4, 2 7 3 - 284 (1993). INFN, Sezione di Torino, 10127 Turin (I)

Photon burst detection of single near-infrared fluorescent molecules. S.A. Soper, Q.L. Mattingly and P. Vegunta. Photon bursts arising from single near-infrared (near-IR) dye molecules transiting a focused Gaussian laser beam in solution with a high detection efficiency can be observed. Near-infrared excitation and detection were used to reduce the fluorescent impurity contribution to the background, which time-gating and spectral filtering cannot overcome in most cases. The single molecule detection apparatus uses a modelocked Ti:sapphire laser as the excitation source and electronics configured in conventional time-correlated single photon counting configuration so that a time gate could be used to help minimize the scattered photon contribution to the background. The photodetector was a solidstate single photon avalanche diode (SPAD), which possesses a large quantum efficiency in the near-IR and a timing response suitable for time-gated detection of dyes with subnanosecond fluorescence lifetimes. The single molecule detection efficiency for the near-infrared dye IR132 was found to be approximately 97%. - Anal. Chem. 65, 740-747 (1993). Dept. Chem., Univ., Baton Rouge, LA-70803-1804 (USA) Evaluation of thermal lens detection in flow injection with high background absorbance. A. Chattier, C.G. Fox and J. Georges. The use of thermal lens spectrometry as a detection technique for the determination of terbium with 4-(2-pyridylazo)resorcinol by flow injection is described. The results, obtained for aqueous and aqueous methanolic solutions, are compared with those previously obtained with a conventional spectrophotometric detector. They are discussed with respect to the dependence of the thermal lens effect on the flow, the solvent composition and the background absorbance. Different parameters such as the chopping frequency, the role of the medium, and the influence of background on the signal intensity were studied. - Analyst 118, 157-160 (1993). Lab. Sci. Anal. U.A. 435, Univ. Claude-BernardLyon, F-69622 Villeurbanne Cedex Quantitative diffuse reflectance and transmittance infrared spectroscopy of nondiluted powders. F. Boroumand, J.E. Moser and H. van den Bergh. An adaptation of Kubelka's general.model of diffuse reflectance and diffuse transmittance of light to nonideal scattering samples is proposed. It is applied to quantitative FT-IR spectrometry of nondiluted surfacederivatized silica powders. Corrections of the measurements are introduced. Effects on the measured data due to the background absorption of the sample and to the specular reflection on its surface are discussed and quantitatively corrected. The possible existence of gradients of the optical properties of the powder medium is taken into account by a numerical adaptation of the model to inhomogeneities of the phenomenological absorption and scattering coefficients K and S. Known concentrations of molecules carrying a cyano functional group as chromophore were covalently anchored on the powder surface. Application of the adapted model gives a quite good description of the measured diffuse reflectance and diffuse transmittance in these cases where the simple Kubelka-Munk function fails. - Appl. Spectrosc. 46, 18741886 (1992). Lab. Etude Poll. Atmos., Sols (F.B., H.v.d.B.), CH-1015 Lausanne (CH) Fast scanning Hadamard spectrnphotometer. R J . Poppi, P.A.M. Vazquez and C. Pasquini. A simple, low-cost, multiplexed Hadamard-type spectrophotometer based on a spinning disk containing 63 separated masks has been constructed to obtain spectral data in time intervals down to 50 ms. Each mask contains 63 resolution elements. Optical localization and identification of the masks were implemented in the disk to avoid misalignment problems. The control of the spectrophotometer and data acquisition was made by using a dedicated single-board microcomputer based on an 8085 CPU. The single board microcomputer sends the data, through an RS-232C interface, to an IBM-AT compatible microcomputer where the Hadamard transform is performed to recover and display the emission, transmittance, or absorbance spectrum. The instrument has been used in the visible range to obtain absorbance data for time-resolved flow injection analysis applications. -- Appl. Spectrosc. 46, 1822 - 1827 (1992). Inst. Quire. Univ. Est. Campinas, Campinas, SP (BR) Gas cell for on-line transmission Fourier transform infrared spectrometry. A.A. Christy, E. Nodland, A. Burnham, O.M. Kvalheim and B. Dahl.

1.1.2

Optical and analogous methods

The design and construction of a gas cell for on-line transmission infrared spectrometry is described to be used with a Spectra-Tech hightemperature- high-pressure (HT-HP) accessory. The heating unit of the accessory was also replaced for dynamic experiments. This cell facilitates the study of the thermal decomposition of compounds by analysing gaseous products with the HT-HP heating accessory and avoids expensive on-line pyrolysis gas cells. The unit has been used to study the online pyrolysis of calcium oxalate and kerogen samples at a heating rate of 50°C min -1. - Vibr. Spectrosc. 4, 365-371 (1993). Dept. Chem., Univ., N-5007 Bergen

151 for the correction of line interferences in ICP-AES. A positioning accuracy of 0.1 pm is required in order to obtain accurate and precise estimates for analyte concentrations. The positioning error in sample scans is more crucial than that in model scans. By the use of an optimization procedure for the positions of scans with the innovations number as the criterion, the wavelength positioning error can be reduced and, correspondingly, the accuracy and precision of analytical results improved. - Appl. Spectrosc. 46, 1816-1821 (1992). Changchun Inst. Appl. Chem., Chin. Acad. Sci., Changchun 130022 (RC)

Simple fiber-optic-based interface to facilitate spectroscopic measurements in supercritical solvents. J. Zagrobelny, Ming Li, Run Wang, T.A. Betts and F.V. Bright. A new fiber-optic-based interface is described to facilitate fluorescence measurements in supercritical solvents. Steady-state and time-resolved measurements are possible, and assembly/disassembly is significantly easier compared to that required for traditional high-pressure optical cell designs. The cell is based on a simple stainless steel plumbing cross and a special, fluid-resistant bifurcated fiber-optic probe. The system is extremely robust, simple to construct and to clean. - Appl. Spectrosc. 46, 1895-1903 (1992). Dept. Chem., State Univ., Buffalo, NY 14214 (USA)

Inductively coupled plasma-microwave induced plasma (MIP) tandem source for atomic emission spectrometry. M.W. Borer and G.M. Hieftje. A new ICP-reduced-pressure MIP tandem source constructed by linking atmospheric-pressure ICP with MIP is constructed and analysed with respect to its capabilities. An aerosol of sample solution is introduced into the ICP where it is vaporized and atomized. The resulting analyte atoms are then extracted from the ICP, through a sampling orifice and into a moderate-pressure region in which a microwave discharge is supported by a Beenakker-type resonance cavity. Experimental results indicate that this novel arrangement provides some of the expected benefits of a tandem source while other figures of merit are only of the same order of magnitude as results obtained by conventional ICP atomic emission spectrometry. - J. Anal. At. Spectrom. 8, 339-348 (1993). Dept. Chem., Univ., Bloomington, IN 47405 (USA)

Use of rapid scan correlation nuclear magnetic resonance spectroscopy as a quantitative analytical method. H. Barjat, P.S. Belton and B.J. Good fellow. Rapid scan correlation (RSC) N M R spectroscopy combines the advantages of rapidity of Fourier transform methods with advantages in dynamic range of continuous wave methods. A systematic investigation of the technique for quantitative analysis has been carried out. The spectrometry is similar to that in conventional N M R techniques but has the advantage of high speed and relatively low cost. A wide range of concentrations can be determined. Developments in data handling are necessary. RSCNMR can be useful as a quantitative method. Application is illustrated by the determination of ethanol in aqueous media and wines over the range 0.01 - 15% v/v. - Analyst 118, 73 - 77 (1993). AFRC Inst. Food Res., Research Park, Colney, Norwich, Norfolk, NR4 7UA (GB)

Design considerations for a pressure-differential tandem source for use in atomic spectrometry. M.W. Borer and G.M. Hieftje. The characteristics of pressure-differential tandem sources for use in AAS are investigated theoretically and experimentally. The union of an atmospheric-pressure inductively coupled plasma (ICP) with a reducedpressure microwave induced plasma (MIP) is used to evaluate experimentally the theoretical arguments. The ICP-MIP combination offers no improvement in detection limits or in ion to atom ratios over what is found in the ICP by itself. These considerations and comparisons suggest possible avenues for future research into pressure-differential tandem sources. - J. Anal. At. Spectrom. 8, 333-338 (1993). Dept. Chem., Univ., Bloomington, IN 47405 (USA)

Optimized prediction of ~3C NMR spectra using increments. Lingran Chen and W. Robien. For the prediction of the 13C N M R spectrum of a given structure a new algorithm of increment calculation [optimized prediction of spectra using increments (OPSI)] is presented, which is based on substructure search strategies starting from the parent ring system and taking into account all possible combinations of partial structures to generate the given target structure. This scheme allows the prediction of the 13C NMR spectrum of any polysubstituted ring system without predefined parameter tables or already prepared substructure/subspectrum files using always the complete information content of a large database. Stereochemical influences are automatically detected. - Anal. Chim. Acta 272, 301-308 (1993). Univ., A-1090 Vienna Atomic emission analysis using a spatial interferometer. C.G. Clarke and M.J. Adams. A simple and small common path interferometer can be successfully employed with diode detection, for simultaneous analysis by atomic emission spectrometry. Emission spectra could be obtained from a range of aqueous alkali metal solutions aspirated into a propane-air flame. Containing no moving components, the assembly is robust and demonstrated to be suitable for simultaneous, multiwavelength analysis. The system can monitor reflection, absorption, emission and fluorescence of liquid and solid samples. - Analyst 118, 220-231 (1993). School Appl. Sci., Univ. Wolverhampton, WV1 1LY (GB) Evaluation of the effect of wavelength positioning errors on Kalman filtering results in inductively coupled plasma atomic emission spectrometry. Jingfu Yang, Zhexiu Piao and Xianjin Zeng. The effect of wavelength positioning errors in spectral scans on analytical results is investigated when the Kalman filtering technique is used

Effect of surfactants in flame atomic absorption spectrometry with pneumatic nebulization: Influence of hydrophobic chain length. A.I. Ruiz, A. Canals and V. Hernandis. The influence of surfactants of different natures and chain lengths on the sensitivity in FAAS is investigated. The improvement in sensitivity is a consequence of a decrease in the aerosol mean drop size. For a given surfactant, the decrease in drop size is caused by the decrease in surface tension in the solutions as the surfactant concentration increases. The shorter the surfactant chain length, the greater is the efficiency of surface tension in diminishing the drop size, to the point that the longest surfactants do not modify drop-size distribution at all and hence do not improve the sensitivity, even though they exhibit the greatest capability to lower the surface tension of the solutions. - J. Anal. At. Spectrom. 8, 109-113 (1993). Dept. Anal. Chem., Univ. Alicante, 03071 Alicante

(E) Analytical characteristics in electrothermal atomization studies of cadmium, copper, germanium, molybdenum, lead and vanadium from pyrolytic and tungsten coated L'vov platforms by atomic absorption spectrometry. Z. Benzo, C. Cecarelli, N. Carrion, M.A. Alvarez, C. Rojas and M. Rosso. A device is developed for coating platforms with the physical vapor deposition-sputler ion plating technique using cheap commercially avallabale and locally constructed components. Tungsten carbide was sputtered onto the surfaces of the platforms and the analytical performance of Cu, Cd, Pb, Ge, V and Mo were tested on the tungsten-coated surfaces and compared with that obtained with standard pyrolytic graphite platforms. Exhausted platforms can be recuperated. An increment in the pyrolysis temperature for the volatile elements Cd and Pb and the improvement in sensitivity for Ge are the major advantages of the tungsten-coated surfaces. The coating system has the advantage that several platforms can be coated simultaneously. - J. Anal. At.

152

1 General analytical methods

Spectrom. 7, 1273 1280 (1992). Centro Quim., Inst. Venezolano Invest. Cient., Caracas 1020-A (YV)

(1993). Dept. Agricult., Nutr. Comp. Lab., BARC-East, Beltsville, MD 20705 (USA)

Role of auxiliary gas flow in organic sample introduction with inductively coupled plasma atomic emission spectrometry. Changkang Pan, Guangxuan Zhu and R.F. Browner. An investigation was carried out to understand the effect of auxiliary gas flow on plasma basic properties by means of a comparison between organic and aqueous sample introduction to an ICP. Changing the auxiliary gas flow rate causes a major shift in the distribution of solvent loading in the plasma sample injection channel, which in turn influences the plasma excitation conditions, causing changes in excitation temperatures and height-resolved emission profiles. Observations of plasmas run with xylenes, amyl alcohol and carbon tetrachloride show that Cz emission signals are the clearest indicator of organic solvent-plasma interactions, changing significantly both with solvent type and with operating power. - J. Anal. At. Spectrom. 7, 1231 - 1237 (1992). School Chem. Biochem., Georgia Inst. Technol., Atlanta, GA 30332-0400 (USA)

Development of an atomic fluorescence spectrometer for the hydrideforming elements. W.T. Corns, P.B. Stockwell, L. Ebdon and S.J. Hill. A miniature argon-hydrogen diffusion flame was used as the atomizer and the analyte elements were introduced as their gaseous hydrides from a fully automated continuous hydride generator. The hydrogen for the flame was chemically generated as a by-product of the sodium tetrahydroborate reduction. Excitation was achieved using a boosteddischarge hollow cathode lamp. Fluorescence wavelengths of interest were selected using an interference filter. A solar blind photomultiplier was used as the detector. The instrument is notably compact and capable of full automation by connection to a personal computer using a DIO card. Detection limits (3cr) of 0.10 and 0.05 pg 1-1 for As and Se, respectively, are reported. A novel atomic fluorescence spectrometer and its suitability for coupling to continuous flow hydride generation and determination of hydride-forming elements, principally arsenic and selenium is developed. - J. Anal. At. Spectrom. 8, 7 1 - 7 7 (1993). PS Anal. Ltd., Arthur House, B4 Chaucer Bus. Park, Watery Lane, Kemsing, Sevenoaks, Kent TN15 6QY (GB)

Flame sample introduction system for inductively coupled plasma atomic emission spectrometry. V. Karanassios, L. Usypchuck, P. Moss and E.D. Salin. An oxygen-hydrogen flame sample introduction system for ICP-AES is proposed. Linking two dissimilar sources was found to be a non-trivial exercise. A total consumption burner oxyhydrogen flame-ICP tandem source was used for the analysis of slurries of marine sediment CRMs with particle diameters of less than 2 ~m. Significant memory effects were observed due to significant analyte loss during the transport. Technical difficulties encountered with the described tandem source as analyte transport, particle size and composition are discussed. Detection limits were 0.3 ppm for Cu, 1 ppm for Mn and 1 ppm for Zn and the precision ranged between 1% and 3% (both determined using aqueous standards). - J. Anal. At. Spectrom. 7, 1243-1247 (1992). Dept. Chem., McGill Univ., Montreal, Quebec (CDN) Palladium nitrate-magnesium nitrate modifier for electrothermal atomic absorption spectrometry. Part 5. Performance for the determination of 21 elements. B. Welz, G. Schlemmer and J.R. Mudakavi. Palladium nitrate-magnesium nitrate (Pd-Mg) mixed modifier can be used nearly universally for the ET-AAS determination of all elements which possibly need a modifier. Significantly higher pyrolysis temperatures could be used for the majority of elements compared with previously recommended modifiers, making possible an efficient removal of concomitants prior to the atomization of analyte elements. NaC1 at a concentration of 10 g/1 had no significant influence on the majority of elements investigated. The concentration of potassium sulfate, which had no influence on the determination, was lower for most of the elements. The tolerance towards NaC1 and K2SO4 increased significantly for a number of elements when the pyrolysis temperature was lowered by 2 0 0 - 300°C and the pyrolysis time was increased. For most of the elements investigated the characteristic mass values were comparable to, or better than published data. For some elements, however, such as bismuth, lead and tellurium, the characteristic mass was significantly higher. This resulted from the high stabilizing power of the Pd-Mg modifier, which necessitated higher atomization temperatures for these elements for which diffusional losses were more pronounced. - J. Anal. At. Spectrom. 7, 1257-1271 (1992). Dept. Appl. Res., Bodenseewerk Perkin-Elmer GmbH, 88662 l]berlingen (D) Graphite furnace atomic absorption spectrometry using a linear photodiode array and a continuum source. J.M. Harnly. The detection limits which can be achieved with a graphite furnace atomic absorption spectrometer based on a continuum source and a linear photodiode array detector (LPDA) are investigated. Wavelength integrated absorbance is computed which asymptotically approaches a maximum as more pixels are used to cover the absorption profile. The read noise of the LPDA was 3800 electrons. The best detection limits were found with an entrance slit-width of 500 gm and 1 6 - 3 2 pixels. The detection limits for Cd, Cu and Ni were comparable to line source atomic absorption spectrometry. -- J. Anal. At. Spectrom. 8, 317-324

A new spray chamber for inductively coupled plasma spectrometry. Min Wu and G.M. Hieftje. A new type of spray chamber is evaluated for ICP-ES. The new design combines gravitational, centrifugal, turbulent and impact loss mechanisms in one apparatus to efficiently remove large droplets, increase transport efficiency and reduce memory effects. Compared with the commonly used Scott-type spray chamber, the new vertical rotary spray chamber has at least 30% higher sample-utilization efficiency, 2 3 times shorter sample clean-out time, half the cost, and simplified construction. Moreover, it offers somewhat better signal-to-background ratios, detection limits, and precision. - Appl. Spectrosc. 46, 19121918 (1992). Dept. Chem., Indiana Univ., Bloomington, IN 47405 (USA)

Design and evaluation of an echelle grating optical system for ICP-OES. T.W. Barnard, M.I. Crockett, J.C. Ivaldi and P.L. Lundberg. An echelle polychromator optical system has been optimized for ICPOES with multichannel solid-state detectors as described in Anal. Chem. 65, 1231 (1993). The optical system has separate output sections for the UV and visible wavelength ranges, which permit high spectral resolution and high optical throughput while covering the spectral range from 167 to 782 nm. A novel component in the UV section corrects spherical aberration, cross-disperses the spectrum, and separates the UV and visible beams. The spectral resolution is improved 3-fold in the UV and 50% in the visible. - Anal. Chem. 65, 1225 - 1230 (1993). Perkin-Elmer Corp., Wilton, CT 06897 (USA) Solid-state detector for ICP-OES. T.W. Barnard, M.I. Crockett, J.C. Ivaldi, P.L. Lundberg, D.A. Yates, P.A. Levine and D.J. Sauer. A solid-state detector has been developed for ICP-OES. The device is based on buried-channel charge-coupled-device(CCD) technology with unique features for optical emission spectroscopy and is matched to a specific echelle grating optical system described in the companion paper. It measures simultaneously 5.7% of the continuous ICP spectrum from 167 to 782 nm with 224 linear photodetector arrays. These arrays are targeted on three to four primary analytical lines for each of 72 elements and cover over 5000 ICP emission lines. This device provides the combination of high quantum efficiency in the UV, low readout noise typical of CCDs, true random-access readout, and charge blooming control for wide dynamic range. In general, the detector has photometric performance (quantum efficiency, noise, dynamic range) equal to or better than photomultiplier tubes for ICP-OES. The simultaneously measured spectral data can be used to correct for spectral interferences and correlated background noise so that analytical detection limits are photon shot noise limited. - Anal. Chem. 65, 1231--1239 (1993). Perkin-Elmer Corp., Wilton, CT 06897 (USA) Interferences in inductively coupled plasma mass spectrometry. A review. E.H. Evans and J.J. Giglio.

1.1.2

Optical and analogous methods

An overview considering 384 references about possible interferences in ICP-MS is given. The most widely used methods to overcome both spectroscopic and non-spectroscopic interferences in ICP-MS involve a sample pre-treatment step to separate the analyte from the matrix. Online column separation methods play a role in the development of chromatographic methods for speciation studies. The development of HR-ICP-MS is expected to continue and should eventually lead to a low-cost instrument to replace the current generation of quadrupole instruments. Such high resolution instruments could be based on a magnetic sector or ion trap, although as yet only magnetic sector instruments have been produced commercially. ICP-MS is now entering into a new phase of development. If the next generation of instruments address the problems discussed in this review, a mature analytical technique will emerge that is capable of robust analyses of the most difficult samples. - J. Anal. At. Spectrom. 8, I 18 (1993). Univ. Plymouth, Anal. Chem. Res. Unit, Dept. Environ. Sci., Drake Circus, Plymouth PL4 8AA (GB) Stored waveform inverse Fourier transform axial excitation]ejection for quadrupole ion trap mass spectrometry. Shenheng Guan and A.G. Marshall. A general method for high-resolution ion excitation, ejection, and isolation is developed from linear response theory for resonant dipolar excitation of the axial z-oscillatory motion of ions in a quadrupole (Paul) ion trap operated in rf-only mode. For a spatially uniform dipolar excitation field, the ion z-oscillation amplitude is directly proportional to the amplitude of the Fourier component of the excitation at the axial oscillation frequency of that ion. Thus, one may specify an arbitrary zmotion frequency-domain spectrum by applying a time-domain stored waveform obtained from the inverse Fourier transform of the corresponding frequency-domain excitation spectrum. The stored waveform inverse Fourier transform (SWIFT) waveform may be tailored for selective ejection or excitation of ions of arbitrary mass-to-charge ratio ranges. The method includes all other possible excitation/ejection waveforms (e.g., single frequency, frequency sweep) as special cases. The effect of collisional damping during excitation is included in the analytical solution of the ion response. - Anal. Chem. 65, 1288-1294 (1993). Dept. Chem., Ohio State Univ., Columbus, OH 43210 (USA) Tandem time-of-flight mass spectrometer. T.J. Cornish and R.J. Cotter. A compact, laser desorption tandem time-of-flight mass spectrometer is developed, which incorporates two dual-stage reflectron analyzers and a collision region for producing product ions by collision-induced dissociation. Selection of ions of a particular mass is accomplished by deflection of ions from stable trajectory angles, entering the second reflectron, while the use of a pulsed valve for introduction of the collision gas obviates the need for differential pumping of the collision region. Initial results are presented, as well as a discussion for optimizing the performance of tandem time-of-flight instruments. - Anal. Chem. 65, 1043 - 1047 (1993). Dept. Pharm. Mol. Sci., Middle Atl. Mass Spectrom. Lab., The Johns Hopkins Univ. School of Med., Baltimore, MD-21205 (USA) Computer aided processing of laser microprobe mass spectra. L. Wouters, D. Michaud and R. Van Grieken. The development and subsequent application of a computer aided method, based on the "library search" strategy, for the interpretation of laser microprobe mass analysis (LAMMA) spectra is described. Such a routine is essential whenever huge amounts of spectra are needed to obtain relevant results, as e.g. in environmental research. The main handicap for a straightforward automation is the poor reproducibility of the analytical technique. - Mikrochim. Acta 110, 3 1 - 4 0 (1993). Dept. Chem., Univ. Antwerp, B-2610 Wilrijk-Antwerp Wavelength-specific resonance-enhanced multiphoton ionization for isomer discrimination via fragmentation and metastable analysis. S.T. Fountain and D.M. Lubman. Resonance-enhanced multiphoton ionization (REMPI) at two wavelengths, 266 and 193 nm, can be used to produce fragmentation from which isomers can be distinguished. Metastable ion energy analysis using a reflectron time-of-flight device is used to analyze the metastable ion

153 products arising from REMPI-induced fragmentation during the flight time to the detector. Metastable ion production is particularly sensitive to variations in wavelength and unique metastable ions are produced at the correct choice of wavelength that allows easy discrimination of isomer pairs. Such discrimination is demonstrated for the isomers LeuTyr and Ile-Tyr at 193 nm, while it is shown that the isomers cannot be distinguished at 266 nm. The isomer pair Trp-Ala and Ala-Trp can be discriminated on the basis of their metastable fragmentations at 266 nm but not at 193 nm. Further, a comparison of fragmentation by REMPI is made to electron impact (EI). - Anal. Chem. 65, 1257-1266 (1993). Dept. Chem., Univ. Michigan, Ann Arbor, MI 48109 (USA) Laser desorption in a quadrupole ion trap: Mixture analysis using positive and negative ions. M.L. Alexander, P.H. Hemberger, M.E. Cisper, and N.S. Nogar. Both negative and positive ions can be generated by laser desorption directly within a quadrupole ion trap. The application of this method to analyze complex samples containing compounds such as explosive residues, metal complexes, and polynuclear aromatic hydrocarbons has been described. In some cases the ability to rapidly switch between positive and negative ion modes provides sufficient specificity to distinguish different compounds of a mixture with a single stage of mass spectrometry. Intensity variation studies can be combined with tandem mass spectrometry experiments and positive and negative ion detection to further enhance specificity. - Anal. Chem. 65, 1609-1614 (1993). Chem., Laser Sci. Div., Nat. Lab., Los Alamos, NM 87545 (USA) Detection of metallic impurities by resonance ionisation mass spectrometry. L. Johann, R. Stuck, P. Kern and P. Siffert. A resonant ionization mass spectrometer based on a quadrupole SIMS coupled to a tunable dye laser has been developed for the detection of trace amounts of metallic impurities in semiconductor materials. The appropriate wavelength to ionize various metals with one color, one resonance (1 + 1) process has been determined. The detection limit of the apparatus has been measured for chromium using different standards with known concentrations of impurities and a value of 0.2 ppm has been found. The result is nearly independent of the matrix. A depth profile with this instrument is presented for titanium in silicon. Analusis 21, 149--152 (1993). Cent. Rech. Nucl., Lab. Phase, 67037 Strasbourg Cedex 2 (F) Analysis of samples containing large amounts of dissolved solids using microsampling flow injection inductively coupled plasma mass spectrometry. A. Stroh, U. V611kopf and E.R. Denoyer. Conventional solution aspiration techniques in ICP-MS can be successfully replaced by sample introduction by flow injection. Especially with samples containing large amounts of dissolved solids good results were obtained. Compared with the aspiration technique, signal depression caused by high salt contents is significantly reduced by the FItechnique. - J. Anal. At. Spectrom. 7, 1201-1205 (1992). Bodenseewerk Perkin-Elmer GmbH, 88662 Uberlingen (D) Imaging-plate X-ray spectrometer for high-resolution particle-induced Xray emission. J. Kawai, K. Maeda and T. Yamane. The use of an imaging plate for the X-ray detector of an X-ray spectrometer is described. The particle-induced X-ray emission (PIXE) spectra of the Fe KLn-L n+l series are recorded using an imaging plate in a flat-crystal type Bragg spectrometer. The imaging plate has been used as a position-sensitive X-ray detector of a high-resolution heavyion PIXE spectrometer. The imaging-plate X-ray spectrometer has the following advantages: (1) the measuring time is short; (2) only a small amount of the specimen is required; (3) the simultaneous detection of many spectral lines is possible; (4) the X-ray spectra are treated as digital data; and (5) high energy-resolution is achievable. - Anal. Sci. 9, 1 7 9 184 (1993). The Inst. Phys. and Chem. Res. (RIKEN), Hirosawa, Wako, Saitana 351-01 (J) Method for quantitative XRF analysis fof inhomogeneons thin specimens. A. Markowicz, N. Haselberger and U. Whai Zin Oo. A simple method for the quantitative XRF analysis of inhomogeneously loaded thin samples is described. Both the theoretical basis of

154

I

the method and the results of an experimental test are presented. To perform quantitative XRF analysis of inhomogeneous samples one has to determine the distribution of the excitation-detection factor (treated as an additional parameter describing the whole XRF set-up) and to evaluate the distribution of the analysed material on the inhomogeneous thin sample. Using the two distributions with the proposed procedure accurate analytical results are obtained. - X-Ray Spectrom. 22, 1 6 0 162 (1993). Int. At. Energy Agency, Agency's Lab., Instr. Unit, A-2444 Seibersdorf (A) Laser-excited synchronous luminescence spectroscopy. C.L. Stevenson and T. Vo-Dinh. Synchronous luminescence (SL) spectroscopy, in which both excitation and emission wavelengths are scanned simultaneously, provides a convenient means to improve selectivity (often dramatically) in the analysis of multicomponent mixtures using room-temperature luminescence. The use of a dye laser as an excitation source for SL at room temperature is reported. The performance of the laser synchronous luminescence system is described for the analysis of four polyaromatic compounds; for one of these - tetracene - the LOD was 680 zeptomotes (10 zl mol) in the vohime probed by the laser. The increase in sensitivity and selectivity due to the laser application is discussed. Appl. Spectrosc. 47, 430-435 (1993). Health, Safety Res. Div., Nat. Lab., Oak Ridge, TN 37831-6101 (USA) Spectrum, multi-element selectivity and elemental response of a linear sulfur emitter in flame photometry. W.A. Aue and Xun-Yun Sun. A new linear mode for sulfur mode is shown for flame photometric detection of sulfur compounds. The luminescence from sulfur compounds in the flame photometric detector (FPD) is dominated by the $2 main-system bands (of about quadratic response) but it contains as well a linear emitter whose "spectrum" could be recorded in the 600 to 850 nm region. In this region sulfur chemiluminescence is a first-order process and varies by a factor of less than two in elemental response among several structurally diverse compounds. The single-channel selectivity of linear sulfur against other FPD-active elements - B, C and H, Sn, Pb, N, P, As, Se, Cr, Mn, Fe, Ru and Os - was measured for a band at ca. 750 nm, and was compared with the selectivity of $2 for its commonly monitored band at 394 nm. The IUPAC detection limit (S/~ = 3) of linear sulfur is 2.10 13 mol S/s and its linear range spans four orders of magnitude. The new linear mode seems preferable to the conventional quadratic one and competitive with other methodologies of organosulfur detection. - J. Chromatogr. 633, 151-162 (1993). Dept. Chem., Dalhousie Univ., Halifax, Nova Scotia B3H 4J3 (CDN)

1.1.3

Chromatographic methods

16th International Symposium on Column Liquid Chromatography. Baltimore, MD (USA), June 1 4 - 1 9 (1992). The proceedings of this meeting are published in two consecutive volumes of Journal of Chromatography. The numerous publications are divided in the following chapters: theory and general, materials and techniques, applications, electrophoresis and other separation methods. The chapter applications is subdivided in chiral separations, pharmaceuticals, proteins and their constituents, biochemical compounds, electrophoresis. This list gives already a short overview of the main field column liquid chromatography. - J. Chromatogr. 631 - 6 3 2 (1993). Open tubular liquid chromatography with flowing retentive liquid. K. Slais and M. Horkfi. A new mode of open tubular liquid-liquid chromatography is suggested where both phases move in the capillary in the same direction: the phase adjacent to the inner surface of the capillary (retentive phase) moves with a lower velocity than that of the mobile phase in the center of the capillary. The principle of the new method is that a pump, via a sampling device, delivers the solution of the retentive phase in the mobile phase. The retentive phase separates from the mobile phase at the begin-

General analytical methods

ning of the capillary. The internal surface of the capillary is modified such that it is wetted by the retentive phase. At the end of the capillary, both the mobile and retentive phases enter a section of the capillary maintained at a temperature at which the solubility of the retentive phase is equal to or higher than at the beginning. As a consequence, the retentive phase dissolves completely prior the entering the detector. J. High Resol. Chromatogr. 16, 194-195 (1993). Inst. Anal. Chem., Acad. Sci., 61142 Brno (CS) The shock layer thickness, a new approach to the study of column performance in non-finear chromatography. I. Optimum finear velocity in frontal analysis. Jie Zhu and G. Guiochon. The relationship between the thickness of the shock layer in frontal analysis and the coefficients of the conventional terms of the plate height equation were studied experimentally. An optimum linear velocity for minimum thickness of the shock layers can be determined using the theory of Rhee and Co-workers. Depending on the retention factor, the optimum velocity in frontal analysis may be larger, but is most often much smaller than in linear chromatography. Experimental results are in excellent agreement with the prediction of the theory. If they could be extended to displacement chromatography, these finding would explain some apparent contradictions found in the literature regarding the influence of the mobile phase flow velocity on the degree of separation between bands achieved in displacement chromatography. - J. Chromatogr. 636, 189-202 (1993). Dept. Chem., Univ., Knoxville, TN 37996-1600 (USA) Simultaneous optimization of pH and micelle concentration in miceliar liquid chromatography. A.H. Rodgers, J.K. Strasters and M.G. Khaledi. An equation is derived which predicts the apparent ionization constants of solutes in micellar solutions. A retention model for ionizable compounds in micellar liquid chromatography is verified. The use of the model for the prediction of retention is illustrated and appropriate optimization strategies for the separation of ionizable compounds in micellar liquid chromatography are discussed. - J. Chromatogr. 636, 203-212 (1993). Chem. Dept., Univ., New Orleans, LA 70148 (USA) Retention indices of phenols for internal standards in reversed-phase highperformance liquid chromatography. Application to retention prediction and selectivities of mobile phases and packing materials. S. Yamauchi. A simple method for predicting the retention times of 31 phenols was established in order to use them as internal standards in HPLC. Relationships between log k' and the numbers of carbon atoms in the alkyl chain of n-alkyl 4-hydroxybenzoates, which are standard compounds for calculating retention indices, showed excellent linearity under all the tested conditions. The retention time of each phenol was Calculated from the retention data for one marker solution consisting of uracil, methyl 4-hydroxybenzoate and ethyl 4-hydroxybenzoate and the retention index of each phenol. The experimentally observed retention times and predicted values agreed to within 10% relative error under several conditions. Using this technique, approximate retention times of phenols can be predicted easily and promptly. In addition, selectivities of the mobile phase and packing materials for phenols are discussed. - J. Chromatogr. 635, 6 1 - 7 0 (1993). Anal. Develop., Formulation Res. Inst., Otsuka Pharmaceutical Co., Ltd., 224-18 Ebisuno, Hiraishi, Kawauchi-cho, Tokushima 771-01 (J) Origin of indirect detection in the liquid chromatography of a neutral sample with an ionic probe using an ODS bonded phase and aqueous mobile phase. L i . M . Glavina and E.F. Cantwell. The mutual effects of the sample on probe sorption and of the probe as sample sorption were studied by the column equilibration technique. This technique is used to explain the indirect UV detection of the nonionic sample butanol on a Partisil 10 ODS-3 HPLC column by adding a constant concentration of anionic probe naphthalene-2sulfonate (NS-) to the mobile phase. Butanol elution is detected as a positive peak and is followed by a negative system peak. Butanol and NS- compete with one another for space in the ODS stationary phase and butanol, in the concentration range 0 - 0 . 0 4 tool/l, does not significantly alter either the solvent strength of the mobile phase or the sorbent strength of the bonded phase, for NS-. This is the origin of indirect

1.1.3

Chromatographic methods

detection of butanol with NS . - Anal. Chem. 65, 268-276 (1993). Dept. Chem., Univ. Alberta, Edmonton, Alberta T6G 2G2 (CDN)

Utility of reversed phase high-performance liquid chromatography for online yield determination of radiochemical separations: Studies with cobalt. S. Subramanian, J.R.W. Woittiez. The potentials of HPLC as a radiochemical technique for multielement separation of neutron irradiated samples are discussed. The detector signal of the eluted components can be used to indicate the chemical yield (percentage recovery) of the analyte. The method promises improved accuracy for elemental analysis despite losses suffered during the various chemical steps. Cobalt as cobalt diethyldithiocarbamate has been used to demonstrate the viability of the concept. The separation was developed on a C18 reverse phase analytical column and optimised on a semi preparative one. The correlation between the signals of ~9Co and 6°Co signals is almost perfect (R = 0.991) regardless of the yield of the chemical process. - J. Chromatogr. 16, 553-572 (1993). Interfac. React. Inst., Univ. Technol., 2629 JB Delft (NL) HPLC method development through retention prediction using structural data. P.P. Csok/m, F. Darvas, F. Csizmadia and K. Valk6. A computerized HPLC method development expert system has been developed that can be used not only by experts but by relatively inexperienced chromatographers. This method is based only on the chemical structure of the solutes to be separated and is able to predict an initial mobile phase composition without any preliminary experiments. The solutes are placed in the predefined capacity factor range to achieve separation. In the subsequent optimization phase, after entering experimental data, an optimized resolution can be usually achieved after two to four HPLC runs. The system calculates 1-octanol/water partition coefficients and recognizes the ionizable groups. The system can be used in reversed-phase and in ion-pair chromatographic modes. - LC-GC Intern. 6, 361 - 3 6 9 (1993). Dept. Pharm. Chem., School Pharm., Univ., London (GB) Practical applications of a chromatography data system using Dynamic Data Exchange. G. Barbay, K. McKiney and L. Robison. To reduce the high amounts of chromatographic data the EZChrom chromatography data system running under Microsoft Windows and using Dynamic Data Exchange is applied with another Window application such as Excel. The cumbersome tasks of data transfer can be speeded. It is shown that vast amounts of data can be automatically transferred into a database from which the data can be transformed into useful information with a significant reduction in time. The steps involved in the reaction analysis and the data reduction process are given in a flow-chart. This data system can save time and transcription errors are minimized. - Intern. Lab. 23(4), 2 0 - 2 3 (1993). Scientific Software Inc., San Ramon, CA (USA) On-line coupling of HPLC, solid-phase extraction (OSP), and TLC (HPLC-OSP-TLC). Assay of 4(5)-methylimidazole in caramel samples. E. M/iller and H. Jork. The coupling of HPLC-OSP-TLC opens up new possibilities in the field of multidimensional chromatography of complex samples. Using a newly developed OSP-2 apparatus the HPLC eluent is exchanged by the inclusion of an on-line solid phase extraction step between the two chromatographic processes and the fraction of interest in the HPLC eluate is focused simultaneously. The on-line coupling of HPLC and TLC of conventional dimensions is accomplished without splitting the HPLC eluate. This on-line coupling, which is capable of automation, has been used for the quantitative determination of 4(5)-methylimidazole in caramel. -- J. Planar Chromatogr. 6, 2 1 - 2 8 (1993). Univ. des Saarlandes, Fachbereich Pharm. und Biol. Chem., Geb/iude 12, 6600 Saarbrficken (D) Retention on non-polar adsorbents in liquid-solid chromatography. Effect of grafted alkyl chains. G. F6ti, M.L. Belvito, A. Alvarez-Zepeda and E. sz. Kovfits. The retention data of a series of solutes of differing polarity are reported on two silica-based adsorbents covered with a dense, chemically bonded, non-polar monolayer, one with and one without grafted C~4

155 alkyl chains as a function of the composition of the binary acetonitrilewater eluent. The sign of the "associated system peak" was also noted. The composition dependence of retention, measured as areal retention volume, could be described on both non-polar stationary phases by the two-parameter Snyder-Soczewinski equation and by the three parameter Schoenmakers equation in a broad but restricted composition range. The areal retention volume on the surface with grafted alkyl chains was equal to or higher than that on the non-swellable, smooth, non-polar DMB surface. Additional retention on the C1, surface increased with increasing adsorption force (retention) on the DMB surface and it was a function of the composition of the eluent. - J. Chromatogr. 630, 1 20 (1993). Lab. Chim. Techn., t~cole Polytech. F6d., CH-1015 Lausanne

Influence of polymer morphology on the ability of imprinted network polymers to resolve enantiomers. B. Sellergren and K.J. Shea. A complete characterization of a number of imprinted polymers prepared in the presence of L-phenylalanine anilide (L-PheNHPh) is carried out. The degree of separation of the D and L enantiomers of PheNHPh (~ value) is used to establish the influence of polymer morphology on polymer performance. Factors that promote stabilization of the template-polymerizable monomer complex prior to polymerization results in polympers with stronger and more selective binding of the substrate. Interestingly, a gel-like non-porous polymer performed similarly to a mesoporous polymer. Performance is also improved upon heat treatment of the polymers and various ways to inhibit the molecular recognition effect are demonstrated. - J. Chromatogr. 635, 3 1 - 4 9 (1993). Dept. Chem., Univ., Irvine, CA 92717 (USA) Evaluation of 3,5-dimethylphenyi carbamoylated ~-, jO-, and 7-cyclodextrins as chiral stationary phases for HPLC. T. Hargitai and Y. Okamoto. Optical resolving power of chiral stationary phases (CSPs) containing 3,5-dimethylphenyl carbamoylated [~-cyclodextrin chemically bonded to silica was compared with those of two commercial stationary phases containing carbamoylated ~-cyclodextrin (~-CD), Cyclobond I SN and Cyclobond I DMP. The influence of cyclodextrins, ~-, 13- and ?-CD, on the enantioselectivity was compared. Each CSP containing different cyclodextrin showed the highest enantioselectivity for different racemates. Separation of racemates were carried out under reversedphase and SFC conditions as well although better selectivity was observed under normal-phase conditions. - J. Liquid Chromatogr. 16, 8 4 3 - 858 (1993). Dept. Appl. Chem., Fac. Engin. Univ., 464-01 Nagoya

(J) Chiral recognition based on hydrophobic entanglement of enantiomers with chiral diamide phases in aqueous media. A. Dobashi, Y. Dobashi, T. Ono, K. Ishida, N. Oshida and S. Hara. Chiral stationary phases from N-(10-undecenoyl)-L-valine tert-butylamide and N-(5-hexenoyl)-L-valine tert-butylamide have a hydrophobic interracial phase by which hydrogen-bond association could be induced for the resolution of enantiomeric N-acylated amino acid esters in aqueous phase liquid chromatography. Increase in organic solvent concentration enhanced polarity due to solvent intercalation in the interracial phase. Enantioselective association between the chiral moiety and enantiomers was hindered by increased intercalation of the less polar organic solvent, thus lessening the degree of chiral recognition, The relationship between the polarity of the interracial phase and extent of enantiomer resolution in liquid chromatography is discussed in regard to the difference in the spacer length. - J. Liquid Chromatogr. 16, 825 841 (1993). Coll. Pharm., Tokyo 192-03 (J) Functionalized polymer particles for chiral separation. T. Hargitai, P. Reinholdsson, B. T6rnell and R. Isaksson. Large amounts of chiral polymer can be irreversibly immobilized to support particles by using residual double bonds in macroporous support particles as "handles" for the grafted polymer. Here the synthetic chiral polymer poly(N-acryloyi-S-phenylalanine ethyl ester) was immobilized by grafting to macroporous polymer particles of various composition and structure. The support particles were prepared by suspension or micro-suspension polymerization of trimethylolpropane trimethacrylate (TRIM), divinylbenzene or by copolymerization of styrene and TRIM.

156 The maximum amount of immobilized chiral polymer and the mechanical properties of the resulting materials varied with the swelling capacity of the parent support particles. Up to 60% (w/w) ofchiral polymer could be immobilized to the pore system. The enantioselectivity of the chiral stationary phases increased with increase in the amount of immobilized chiral polymer. - J. Chromatogr. 630, 7 9 - 9 4 (•993). Dept. Chem. Engin. 2, Univ., S-22100 Lund

Preparation and evaluation of cross-linked polyacrylate stationary phases for open tubular liquid chromatography. Y. Ruan, G. Feenstra, J.C. Kraak and H. Poppe. Polyacrylate films in 12 gm i.D. fused silica capillaries were obtained by in-situ photopolymerization of acrylates. Due to the incorporated lauryl moiety in the layer considerable retention could be achieved for polar compounds with aqueous mobile phases. The efficiency of the prepared columns approximates to the theoretical value. The polyacrylate films appear to be extremely stable even under strong basic conditions. The films swell considerably in the presence of non-polar solvents. - Chromatographia 35, 597-606 (•993). Lab. Anal. Chem., Univ., 1018 WV Amsterdam (NL) Characterization of spherical polymer packings from N,N-dialkyl acrylamide for reversed-phase liquid chromatography. C. Hirayama, H. Ihara and S. Nagaoka. Chemically stable (alkali- and acid-resistance) and totally organic polymer packings were prepared using N,N-dialkyl acrylamide monomers and their chromatographic properties were investigated. The packings can be prepared by one-step polymerization. The hydrophobic parts of polymer packings were composed of N-methyl N-octadecyl acrylamide and N,N'-dibutylhexane N,N'-diacrylamide was used as a crosslinking monomer. The hydrophobicity of the spherical particles was easily controlled varying by the monomer ratio in the suspension polymerization. As for RPLC behavior, the packings had no abnormal adsorption for ionic substances and showed no excessive retention and no peak tailing for carbonyl compounds. - J. Chromatogr. 16, 6 4 7 659 (1993). Dept. Appl. Chem., Fac. Engin., Univ., Kumamoto 860 (J) Normal-phase high-performance liquid chromatography with highly purified porous silica mierospheres. J.J. Kirkland, C.H. Dilks, Jr. and J.J. DeStefano. The characteristics of the new porous silica microsphere Zorbax RxSIL for use in normal phase HPLC are studied. The new silica shows special promise for developing rugged separation methods to analyze polar and basic compounds that traditionally are handled by reversedphase chromatography. - J. Chromatogr. 635, 1 9 - 30 (1993). Rockland Technologies, Inc., Newport, DE 19804 (USA) Reversed-phase high-performance liquid chromatographic separation of small molecules on nonporous C18 silica gel column. H. Itoh, T. Kinoshita and N. Nimura. An investigation was carried out on the use of nonporous silica packing materials for the reversed-phase separation of low molecular-weight compounds like alkyl-benzenes. Nonporous macroporous (pore diameter; 30 nm), and microporous (pore diameter; 10 nm), C18 bonded silica columns under both isocratic and gradient elution conditions were compared. Unter isocratic conditions, column efficiency of nonporous silica was inferior to that of others. In case of the gradient elution, the nonporous silica column gave the most favorable separation in a short time. Fast separations of small molecules on the nonporous column could be performed by using a conventional FIPLC system with a steep gradient, because the void volume of the nonporous packing was extremely small. Various series compounds such as fatty acid derivatives, phenylthiohydantoin amino acids, and vitamins were well separated within 1 or 2 min on the C18 nonporous silica column under steep gradient conditions. - J. Liquid Chr0matogr. 16, 809--823 (1993). School Pharm. Sci., Kitasato Univ., Minato-ku, Tokyo 108 (J) Protamine-coated silica gel as packing material for high-performance liquid chromatography of carbohydrates. S. Yamauchi, N. Nimura and T. Kinoshita.

1 General analytical methods Protamine-coated silica gel support for partition chromatography was found to be readily prepared by passing the protein through a silica gel layer. Application of the support to HPLC provided versatile separation of mono- and oligosaccharides, and sugar alcohols. The support could be operated at room temperature and gave excellent recovery for the reducing monosaccharides such as mannose and ribose for which a conventional aminoalkyl-bonded phase column gave poor recovery. Acetonitrile/water-mixtures (85:15 or 80:20) are used as mobile phases. - Analyst 118, 161-164 (1993). Centr. Res. Lab., SS Pharmaceutical Co., Narita-shi, Chiba 286 (J)

Estimation of silanol groups in silica-based packings for liquid chromatography from gas chromatographic retention of cyclohexane and benzene. T. Takeuchi, T. Miwa and N. Nagae. The percentage of residual silanol groups of bonded-phase materials is estimated by means of measuring the retention behaviour of cyclohexane and benzene in GC. Differences in capacity factors (Ak') for these two hydrocarbons were related to the surface area of the packing materials. For untreated silica gels, the Ak' value increased with increasing total surface area of the column employed and measurement of Ak' for chemically-bonded stationary phases allowed estimation of accessible residual silanol groups. - Chromatographia 35, 375-380 (1993). Fac. Engin., Gifu Univ., Yanagido, Gifu 501-11 (J) Vinyl modification of fused-silica surfaces in polysiloxane-coated 1 0 - 50 pm I.D. capillaries for open-tubular liquid chromatography. K. G6hlin and M. Larsson. Three different pretreatment methods based on vinyl-containing reagents were tested in 50 pm I.D. fused-silica capillaries. The modified capillaries were coated with the stationary phase PS 255, a polydimethylvinylsiloxane, and cross-linked. The procedure did not improve the immobilization of the stationary phase. The selectivity shift for thin stationary phase films was observed also after deactivation of the fusedsilica surface. - J. Chromatogr. 634, 31 - 3 9 (1993). Dept. Anal. Marine Chem,, Chalmers Univ. Technol., Univ., S-41296 G6teborg Synthesis and characterization of highly stable polymer-coated aminosilica packing material for high-performance liquid chromatography. H. Kutsuna, Y. Ohtsu and M. Yamaguchi. To develop a silica-based amino-bonded stationary phase for HPLC the silica surface was first coated with a silicone polymer monolayer and an amino functionalitY was subsequently attached to the polymer layer. The polymer-coated amino-bonded phase showed improved stability and separation in the analysis of carbohydrates and nucleotides over conventional aminopropylsilylated silicas. - J. Chromatogr. 635, 1 8 7 193 (1993). Basic Res. Lab., R&D Headquarters, Shiseido Co., Ltd., Yokohama 223 (J) Investigations into the use of poly(3-methylpyrrole-4-carboxylic acid) coated silica as a chromatographic stationary phase. H. Ge, K.J. Gilmore, S.A. Ashraf, C.O. Too and G.G. Wallace. Silica supports coated with poly(3-methylpyrrole-5-carboxylic acid) were tested as stationary phase for the separation of various compounds. The predominant retention mechanisms are based on reversed phase anion exclusion and cation exchange, which are influenced by solution conditions. The new stationary phase can be used for the separation of proteins. - J. Liquid Chromatogr. 16,1023 - 1044 (1993). Mat. Technol. Div., Singapore Inst. Stand., Ind. Res., 1 Science Park Drive, Singapore 0511 (SGP) Enantiomer separation by HPLC on reversed phase silica gel coated with copper(II) complexes of (R,R)-tartaric acid mono-amide derivatives. N. Oi, H. Kitahara and F. Aoki. (R,R)-tartaric acid mono-(R)-l-(et-naphthyl)ethylamide [I] and (R,R)tartaric acid mono-n-laurylamide [II] coated on ODS-silica gel were used for the direct separation of a number of amino acid, hydroxy acid and amino alcohol enantiomers with water or organic eluents containing copper(II) ion as a mobile phase. The enantioselectivity of the phase [I] was superior than that of the phase [II]. - J. Liquid Chromatogr. 16,

1.1.3 Chromatographic methods

157

893-901 (1993). Sumika Chem. Anal. Service, Ltd., Konohana-ku, Osaka 554 (J)

tion with continuous measurement is justified. J. Liquid Chromatogr. 16, 1769-1781 (1993). IN/US Systems, Inc., Fairfield, NJ 07004 (USA)

Cellulosic chiral stationary phase under reversed-phase condition. A. Ishikawa and T. Shibata. Chiral stationary phases on polysaccharide esters have been applied under reversed-phase conditions to attain good chiral separations on the cellulose-based-columns. A simple mixture of water and an organic solvent as the mobile phase gave sufficient separation of an electrically neutral racemate. It was necessary to add an anionic chaotrope for the separation of a basic racemate and a small amount of a strong acid for an acidic one. - J. Liquid Chromatogr. 16, 859-878 (1993). Daicel Chem. Ind., Ltd. Res. Center, Him@ 671-12 (J)

Improved ultraviolet detection in high-temperature open-tubular liquid chromatography (HT-OT-LC). N.M. Djordjevic, D. Stegehuis, Guanghui Liu and F. Erni. With a "Z-shaped" microflow cell it is possible to enhance the S/N ratio in HT-OT-LC. This cell should be applied for separations in which detection is the main problem. Furtheron the detection limit can be significantly enhanced using an optical fibre bundle. - J. Chromatogr. 629, 135-14l (1993). Anal. Res., Develop., Sandoz Pharma, CH-4002 Basle

Design of mobile phase composition for liquid chromatography with an internal pH gradient. M. Jane~ek and K. Slais. A method is suggested for calculating the mobile phase composition for ion exchange chromatography with an internal pH gradient. An internal pH gradient of the desired steepness can be achieved providing the titration curve of the sorbent is known. The procedure has been verified by use in the design of a mobile phase composed from few anionic buffers for generation of internal pH gradient on a microcolumn packed with a cation exchanger with carboxylie functional groups. The gradient profiles obtained with three buffer components are smooth and in the pH range 3--8 not very different from linearity as predicted by theory. - Chromatographia 36, 246-250 (1993). Inst. Anal. Chem., Acad. Sci., 61142 Brno (Czech Republic) Tandem detectors to quantitate overlapping chromatographic peaks. F.L. Herman. An analytical method for quantitating chromatographically overlapping components using multiple detectors that exhibit comparable, although not identical, selectivity for the coeluting species is discussed. Equations are derived for quantitating two overlapping components using two detectors with either an internal or an external standard analytical method. Quantitation is possible even when the components exhibit complete overlap. The internal standard method is applied to the analysis of acrolein/propionaldehyde mixtures using a tandem photoionization/flame ionization detector. Component concentrations are determined with a relative accuracy of 3.4% when both overlapping components are present at equal concentrations. When the components are present at different concentrations, greater relative accuracy is obtained for the more highly concentrated component. - Anal. Chem. 65, 1023 - 1027 (1993). Air Prod. and Chem., Inc., Allentown, PA-] 8195 (USA) Organic fuelled flames in selective ionization detectors for chromatography. P.L. Patterson. By introduction of methane as a fuel for the flame in two flame-based ionization detectors - a remote FID (RFID) and a Flame Thermoionic ID (FTID) are designed. The RFID detects long-lived negative ions produced in the flame by the combustion of lead, tin, phosphorus, or silicon compounds. The FTID re-ionizes and detects neutral electronegative products generated by combustion of nitrogen, halogen, or phosphorus compounds. An organic-fuelled RFID can detect 1 pg Pb (Sn, P)/sec with a selectivity of the order of 106 versus hydrocarbons. An organic fuelled FTID is applicable to detection of compounds at nanogram and higher levels. FTID selectivity for PCB compounds in a transformer oil matrix is of the order of l0 s : 1. - Chromatographia 36, 225-233 (1993). Detector Engin. & TechnoL, Walnut Creek, CA 94598 (USA) t-Particle detection in HPLC by flow-through monitoring vs. liquid scintillation counting. E. Rapkin. Continuous-flow measurement has many advantages in radio-HPLC measurements. Statistical considerations suggest that fraction collection followed by scintillation counting offers the possibility of higher sensitivity and accuracy for low-activity measurement of radioactivity in HPLC eluates. However, when the randomness associated with fraction collection is taken into account, presumed advantages of fraction collection largely or wholly disappear and the trend to replace fraction collec-

Rapid scan microvoltammetric detection for liquid chromatography. J.G. White, A.L. Soli and J.W. Jorgenson. Scanning electrochemical detection employing carbon fibers are tested for HPLC. A 9 gm carbon fibre is used as carbon microvoltammetric electrode which is placed in the eluent as it flows into a cell. Effects of scan rate and flow rate are discussed. Detection limits of 10 -6 M (1.1 ng, injected) have been obtained for hydroquinone, and the detector is linear over four orders of magnitude in concentration. The twodimensional resolving power is demonstrated using a mixture of six standards and the detector is used for the identification of caffeine in tea. - J. Liquid Chromatogr. 16, 1489-1496 (1993). Dept. Chem., Eckerd Coll., St. Petersburg, FL-33733-2560 (USA) A new type of polarimeter HPLC detector. W. Zelenka, A. Leiminer and A. Mannschreck. A detector for chiral molecules which is based on the measurement of their respective specific rotation is presented. This long known polarographic principle is adapted for the HPLC and used for compounds like sugars and fragrance compounds. The detector uses the Faraday effect to compensate the rotation angle caused by the optically active sample. This compensation current is directly proportional to the rotation angle. The determination of the rotation angle of the sample can be carried out by a simple current measurement without any mechanically moving parts. Detection limits for D-(-)-fructose and sucrose as low as 0.0005 mg could be achieved with this new device. - GIT Fachz Lab. 37, 97-103 (1993). IBZ Mel3technik GmbH, Vahrenwalder Str. 7, W-3000 Hannover 1 (D)

A reagentless coimmobilized alcohol biosensor as a detection unit in column liquid chromatography for the determination of methanol and ethanol. G. Marko-Varga, K. Johansson and L. Gorton. A reagentless enzyme electrode based on coimmobilized alcohol oxidase and horse radish peroxidase has been inserted as a detection unit in column liquid chromatography for the analysis of methanol and ethanol. The enzymes were covalently immobilized in a carbon paste electrode material in the presence of polyethylenimine. Optimization regarding the sensitivity and selectivity of this sensor and its compatibility with the reversed phase chromatographic system was outlined. A PLRP-S polymer based separation column was used with phosphate buffer as the mobile phase. The effect of the inclusion of polyethylenimine in the carbon paste and its influence on the registered chromatograms was investigated. The selectivity of the enzyme electrode was also determined by injection of other easily oxidisable interfering species normally present in biological samples. - Quire. Anal. 12, 24 29 (1993). Dept. Anal. Chem., Univ. Lund, S-22100 Lund (S) Enzyme based detection systems in column liquid chromatography extension of selectivity and sensitivity. G. Marko-Varga, L. Gorton, E. Dominguez and D. Barcel6. A review concerning 108 references is given about enzyme based detection systems in column liquid chromatography using systems based on both enzyme reactors in conjunction with a flow through detection device and enzyme electrodes. Optimizations for making detection principles compatible with chromatographic systems and applications made in our laboratories are presented for the analysis of e.g. carbohydrates, amino acids, ethanol and catecholamines. Gel-permeation chromatography and mass spectrometry are used as complementary techniques for qualitative and quantitative analysis of complex

158 samples. - Chromatographia 36, 381 - 3 9 8 (1993). Dept. Anal. Chem., Univ. Lund, Box 124, S-22100 Lund (S)

High-flow ion spray liquid chromatography/ma~ss spectrometry. G. Hopfgartner, T. Wachs, K. Bean and J. Henion. The application of high-flow (up to 2 ml/min) ion spray to the LC/ MS determination of compounds of pharmaceutical and environmental interest with standard (HPLC) columns without established postcolumn splitting of the flow is shown with the use of a nonvolatile mobile phase buffer, potassium phosphate, for the LC/MS determination of lysergic acid diethylamide (LSD). To achieve practicality and analytical ruggedness of the system, a liquid shield is placed between the sprayer and the ion sampling capillary, resulting in full-scan low-nanogram determination of quaternary ammonium drugs. The system also allows the use of gradients. The analysis of carbamate pesticides and in particular for mexacarbate in pond water is carried out with the described system. - Anal. Chem. 65, 439-446 (1993). Drug Test., Toxicol., New York State Coll. Veter. Med., Cornell Univ., Ithaca, NY 14850 (USA)

1 General analytical methods decades for DIEM and TTBL, and two decades for the TRBL. The precision of the technique was between 1 and 5% relative standard deviation for 5 ng injections of the compounds of interest. - J. Anal. At. Spectrom. 7, 1173-1181 (1992). Univ. Cincinnati, Dept. Chem., Cincinnati, OH 45221-0172 (USA) Multi micro high-performance liquid chromatography. O.I. Voroshilova and R.E. Kaiser. A micro HPLC system was developed which is based on the use of two series-coupled beds of chemically differing stationary phases in one packed fused silica columns which results in physically changeable selectivity. The selectivity change, in fine repeatable steps, was possible by the stepwise moving of a tube oven, covering only 50% of this "tandem column". Each step of selectivity started with a position change of the oven, thus heating up a fresh position of the more polar and the non-polar column bed. As the chromatogram is thus repeated under these new selectivity conditions, multiple chromatograms result. Chromatographia 36, 4 7 - 5 2 (1993). Inst. Chromatogr., 67098 Bad Diirkheim (D)

Operation of a quadrupole ion trap (QIT) for particle beam LC/MS analyses. B.L. Kleintop, D.M. Eades and R.A. Yost. The performance of a QITMS as a mass spectrometric detector for particle beam (PB/LC/MS) is described. The PB interface was directly coupled to a QITMS without the use of an external ion source; vaporization of the particle beam and ionization by electron ionization (EI) were accomplished within the ion trap. Ions from residual LC solvent initially caused space charging and a significant extent of chemical ionization (CI), which degraded the quality of EI mass spectra. Ejection of solvent ions prior to mass analysis minimized both space charging and CI, which allowed acquisition of EI spectra that compared favorably to EI spectra obtained from pure samples vaporized offofa solids probe and to library EI spectra. Isocratic LC/PB/QITMS analyses for several pesticides show lower limits of detection than those reported for LC/PB/MS analyses on PB systems using quadrupole mass analyzers. Typically nonlinear calibration curves are produced, although linear calibrations have been observed for some analytes. For diuron linear calibration curves from 20 to 500 ng with correlation coefficients (r 2 = 0.9984) are obtained. Anal. Chem. 65, 1295-1300 (1993). Dept. Chem., Univ. Florida, Gainesville, FL-32611-2046 (USA)

Use of an open-tubular trapping column as phase-switching interface in on-line coupled reversed-phase liquid chromatography/capillary gas chromatography. H.G.J. Mol, J. Staniewski, H.-G. Janssen, C.A. Cramers, R.T. Ghijsen and U.A.Th. Brinkman. Open-tubular traps can be used for phase-switching in coupled RPLC/ GC. The phase-switching process involves sorption of the analytes of interest from a methanol-water mobile phase into the stationary phase of an open-tubular column, removal of the aqueous phase by purging the trap with nitrogen and desorption of the analytes with hexane. Water elimination carried out appears to be highly efficient. In the sorption step the sampling flow-rate and the capacity factors of the analytes in the trap are critical parameters. Using a 2 m × 0.32 mm I.D. trap with a swollen 5-gin stationary phase at flow-rates not exceeding 100 Ixl/min, polycyclic aromatic hydrocarbons are trapped quantitatively from 300 ~tl of aqueous phases containing up to 65% (v/v) of methanol. For desorption 7 0 - 1 2 5 gl of hexane are needed. -- J. Chromatogr. 630, 201-212 (1993). Fac. Chem. Engin., Lab. Instrum. Anal., Univ. Technol., 5600 MB Eindhoven (NL)

Micro flow rate particle beam interface for capillary fiquid chromatography/mass spectrometry. A. Cappiello and F. Bruner. A new laboratory-made aerosol generator is described to interface the effluent from a HPLC packed capillary column to a quadrupole mass spectrometer. The new coupling device is designed to be fully compatible with a commercially available desolvation chamber and the momentum separator of a Hewlett-Packard 59980B particle beam unit. The aerosol generated by minimal solvent input ( 1 - 5 p.1/min) allows an improved signal response for high water content mobile phases, yielding improved chromatographic performance during gradient analysis. Sensitivity is also improved by the scaled-down flow rate. Reversed-phase analysis has been performed on a mixture of human hormones using the new interface. The lowest detectable amount of a test sample (caffeine) was 0.1 ng (S/N = 3) for the m/z 194 ion. -- Anal. Chem. 65, 1281-1287 (1993). Ist. Sci. Chim., Univ., 1-61029 Urbino (I)

Preparation of open tubular columns for reversed-phase high-performance liquid chromatography. A.L. Crego, J.C. Diez-Masa and M.V. Dabrio. A new method is developed to prepare a layer of silica gel on the inner wall of smaller inner diameter (50, 10 and 5 ~m) fused-silica capillaries using hydrolytic polycondensation and ulterior gelling of tetraethyl orthosilicate (TEOS) in a pH-fixed water-methanol solution. Parameters controlling the porosity and thickness of the silica layer (such as preconditioning of the fused-silica wall, time and temperature of the pregelling process, and pH at which hydrolysis takes place) and the yield of the C1 s bonding reaction are studied. Values of reduced plate height around 0.4 were obtained for 10- and 3-gm-i.d. columns. Using 5-gin columns 0.5 × 106 plates m -1 and 1000 plates s -1 were obtained. The reproducibility of the method in terms of k" (RSD = 1 2 - 1 4 % ) and reduced plate height (RSD = 4 - 5 % ) from column to column is quite good. Some applications of these open capillary columns for the separation of PAHs are presented. - Anal. Chem. 65, 1615 - 1621 (1993). Inst. Quim. Org. Gen., Juan de la Cierva, 3 28006 Madrid (E)

Multi-element detection for supercritical fluid chromatography by inductively coupled plasma mass spectrometry. J.M. Carey, N.P. Vela and J.A. Caruso. It is possible to obtain multi-element supercritical fluid chromatograms (SFC) with ICP-MS detection for organomercury and organolead compounds. Detection is usually performed in a single-ion monitoring mode. The applicability of utilizing time-resolved acquisition (TRA) software for quantitative determinations using SFC was investigated and compared with results obtained for single-ion monitoring modes. Detection limits were found to be approximately 5 - 10 pg for diethylmercury (DIEM) using TRA detection and 3 pg using single-ion monitoring detection. The detection limits of tetrabutyllead (TTBL) and tributyllead (TRBL) acetate were found to be 0 . 7 - 3 and 5 0 - 1 0 0 pg, respectively, for the TRA acquisitions, and 0.5 and 10 pg for single-ion monitoring measurements. The calibration graphs were linear over three

Influence of linear velocity and multigradient programming in supercritical fluid chromatography. S. Kiippers, M. Grosse-Ophoff and E. Klesper. The influences of plate height, resolution and gradient programming on the performance of supercritical fluid chromatography separations are extensively investigated and discussed, practically and theoretically. - J. Chromatogr. 629, 345-359 (1993). Lehrst. Makromol. Chem., Techn. Univ., W-5100 Aachen (D) Retention time and peak width models for capillary column supercritical fluid chromatography: Part I. Isothermal and isopycnic separations; II. Density programmed separations at different temperatures. P. Petersson, N. Lundell and K.E. Markides. Prediction of retention is possible as functions of temperature and density. On this basis a new model usuable for the prediction of retention

1.1.3

Chromatographic methods

time and peak width in isothermal and isopycnic separations performed by open tubular column SFC is presented. For density programmed open tubular SFC nine nonprogrammed dead time measurements in combination with four programmed measurements of retention times and peak widths are needed for accurate prediction. The accuracy of the models is evaluated with compounds having different molecular weight, size and functionality in different parts of the accessible experimental domain. - Chromatographia 35, 4 7 9 - 4 9 2 (1993). Dept. Anal. Chem., Univ., 75121 Uppsala (S)

Enantiomer separation by complexation gas and supercritical fluid chromatography on immobilized polysiloxane-bonded uickel(II) bis[(3heptafluorohutanoyl)-10-methyleue-(1R)-camphorate] (Chirasil-nickel). M. Schleimer and V. Schurig. The synthesis of a polysiloxane containing chemically bonded chiral metal complex derived from nickel(II) bis[(3-heptafluorobutanoyl)-10methylene-0 R)-camphorate] (Chiral nickel) and its effective immobilization on the inner surface of fused-silica capillaries by thermal treatment is described. The immobilization properties were dependent on the content of residual reactive Si-R groups in the polymer backbone (R = OCHa, H). The immobilized Chirasil-nickel stationary phase was employed for the analytical enantiomer separation of coordinating solutes by high-resolution capillary gas and supercritical fluid chromatography. The temperature limit of analysis was raised to 1 7 0 180°C for temperature-programmed runs and to 140-150°C under isothermal conditions. - J. Chromatogr. 638, 8 5 - 9 6 (1993). Inst. Org. Chem., Univ., W-7400 T/ibingen (D) Evaluation of microbore and packed capillary column chromatography with an ethylvinylbenzene-divinylbenzene polymeric packing material and supercritical ammonia as the mobile phase. D.E. Raynie, K.M. Payne, K.E. Markides and M.L. Lee. The use of ammonia as a mobile phase for high-resolution SFC was studied. A highly cross-linked ethylvinylbenzene-divinylbenzene polymeric packing material (5-gm diameter) in microbore stainless-steel and nickel capillary tubing demonstrated reasonable efficiencies (ca. 10 000 15000 plates m 1, after initial exposure to ammonia) without phase degradation as previously observed when using open-tubular capillary columns. However, ammonia treatment caused an initial rapid loss in efficiency (ca. 42%) for reasons as yet undetermined. The polymeric packing materials were much more inert than conventional silica-based packing materials. Separations ofpotar drugs, underivatized amino acids and defoliant herbicides are shown. - J. Chromatogr. 638, 7 5 - 8 3 (1993). Dept. Chem., Brigham Young Univ., Provo, UT 84602 (USA) Addition and measurement of water in carbon dioxide mobile phase for supercritical fluid chromatography. Dongiin Pyo and Doweon Ju. For the addition of water to supercritical CO2 this is delivered from the pump to a g-Porasil column that is saturated with water. After passing through the g-Porasil column, supercritical CO2 is changed to a new mobile phase with different polarity, and it is possible to separate polar samples by using this new mobile phase. The amount of water dissolved in supercritical CO2 is measured by an amperometric microsensor, which is prepared from a thin film of perfluorosulfonate ionomer. - Analyst ll8, 253-255 (1993). Dept. Chem., Kangweon Nat. Univ., Kangweon-do (Korea) Calibration of spectrophotometric detectors for supercritical fluid chromatography. U. Meier and Ch. Trepp. A method for rough calibration of spectrometric detectors in SFC and for approximate comparison of peak values obtained on different detectors at different SFC operating parameters is introduced. The method is based on the molar absorptivity of the analytes. It allows calibration independent of detector specifications, flow cell geometry and operating parameters. SFC hardware requirements and operational and calibration procedures that are prerequisites for accurate quantitative SFC results were considered. The method was tested with samples of fatty acid glycerol esters, a-tocopherol (vitamin E) und its acetate in carbon dioxide-ethanol eluents with two different UV detectors. Errors and shortcomings of the method that narrow the scope of its applications

159 are discussed. - J. Chromatogr. 629, 361-370 (1993). Inst. Process Engin., Cryogenics, Swiss Fed. Inst. Technol., CH-8092 Zurich

Use of packed column supercritical fluid chromatography (SFC) with ozone-based sulfur chemiluminescence detection (SCD). A.L. Howard and L.T. Taylor. A packed column SFC/SCD interface was tested. In comparison to the capillary SFC/SCD the increased flow rate of CO2 did not affect the sensitivity of the detector. Detectivities of 2 pg S/s and 1 pg S/s (S/ N = 3) were obtained when capillary SFC (60-nl injection) and packed column conditions (500-nl injection) were employed, respectively. Detector linearity was 3 - 4 orders of magnitude. Methanol-modified CO2 was also demonstrated to be compatible with the SCD even with the high mobile phase flow rate. The analyses of polycyclic aromatic sulfurcontaining hydrocarbons (PASH), diesel fuel, and sulfonylurea herbicides were explored as possible applications. - Anal. Chem. 65, 7 2 4 729 (1993). Dept. Chem., Virginia Polytech. Inst., State Univ., Blacksburg, VA-24061 (USA) Electrostatic theory of ion-pair chromatography. Multi-site occupancy model for modifier and solute adsorption. J. Narkiewicz-Michatek. Stahlberg's application of the Gouy-Stern approach in ICP is further deveioped taking into account the multiple-site occupancy character of adsorption of amphiphilic modifiers as well as analytes. The theoretical expressions for the capacity coefficients obtained in this way are also able to explain experimental findings, previously classified as exceptional deviations from the predictions of the electrostatic theories. Chromatographia 35, 527-538 (1993). Dept. Theoret. Chem., Univ., 20-031 Lublin (PL) Two-dimensional conductometric detection in ion chromatography: Sequential suppressed and single column detection. I. Berghind, P.K. Dasgupta, J.L. Lopez and O. Nara. An easy approach of combining suppressed and non-suppressed ion chromatography by using the abilities of a PC to compute time-multiplex input/output analog signals of a dual channel bipolar pulse conductometric detection system is described. Following the detector of a conventional NaOH eluent suppressed IC system, a constant concentration of NaOH is introduced by an in-line microelectrodialytic NaOH generator, and this is followed by a second conductivity detector. The second detector background is typically maintained at a level of 20 - 30 gS/cm (corresponding approximately to 0. I mM NaOH), and the detector output is the same as what would be observed in a single column mode with a low concentration NaOH eluent. Together, the two detector outputs provide detectabilities at the microgram per liter level across the pKa range--from fully dissociated to very weak acids (up to pKa 9.5). Excellent linearity of response is observed, and the system provides qualitative information about peak purity and eluite pK,. - Anal. Chem. 65, 1192 - 1198 (1993). Dept. Chem. Biochem., Texas Tech Univ., Lubbock, TX 79409-1061 (USA) The wall effect in overpressured layer chromatography (OPLC). L. Botz, E. Wehrli and O. Sticher. The importance of the interaction between the sorbent surface and the cover sheet in OPLC is studied. The interaction has been demonstrated with electron micrographs and has proved for the first time that the cover material does conform to the outer surface of the layer of sorbent. The increased sorbent permeability at higher external pressures supports the hypothesis that eluent flow is enhanced by the wall effect. The reduced wall effect obtained on HPTLC layers shows that the smaller particle size has a beneficial effect on the interaction. - J. Planar Chromatogr, 6, 1 3 - 2 0 (1993). Janus Pannonius Univ., Dept. Bot., H7644 P6cs (H) Advanced simplex optimization of two-factor selectivity by high-performance thin-layer chromatography. Q.S. Wang, W.Q. Xie and D.P. Fan. A computer-assisted mixture-design simplex method is developed for simultaneous two factor optimization of the separation of a mixture of 5 benzoic acid derivatives in reversed-phase HPTLC and 12 PTH amino acids in normal phase HPTLC. The method is based on a special polynomial estimated from nine experimental runs, using the Rv difference

160 as the selection criterion, with connection to a general simplex method for optimization usisng a microcomputer. Excellent agreement is obtained between predicted data and experimental results. For the optimization the computer program SDO_T was created. -- Chromatographia 35, 149-152 (1993). Nat. Lab. Elem.-Org. Chem., Nankai Univ., Tianjin 300071 (RC)

Quantitative thin layer chromatography part 12: Quality assessment in QTLC. M. Prosek, M. Pukl, L. Miksa and A. Golc-Wondra. A program is developed to check the quality of TLC data obtained by quantitative measurement. Samples are applied as bands with a Linomat IV. Each track is scanned twice, the first time after application and the second time after development; the length of the slit used is 50% that of the band. The errors arising from the scanner, applicator and chromatography, given in relative standard deviations, can be determined from the additivity bf variances of these measurements. The difference between the integrated areas of standards and samples is examined in order to determine whether this contribution is a random or systematic error. - J. Planar Chromatogr. 6, 6 2 - 6 5 (1993). Nat. Inst. Chem., Hajdrijova 19, Ljubljana (Slovenia) Computer-aided optimization of stepwise gradient and multiple-development thin-layer chromatography. W. Markowski and E. Soczewinski. Equations for the computation of the final RE values for mobile phase gradient development and gradient multiple development are presented. Computer simulations of gradient development for both modes of thinlayer chromatography are discussed for the preliminary optimization of gradient programs. - Chromatographia 36, 330-336 (1993). Dept. Inorg. Anal. Chem., Med. Acad., 20081 Lublin (PL) Computer-assisted optimization of HPTLC separation of mixtures of unknown composition using UV spectra. Wang Qin-Sun, Zhan Zhuang-Ping and Wang Yi-Hong An optimization procedure for the selection of the optimum mobile phase for HPTLC separations is developed which is based on a computerassisted spot order identification, by comparison of the UV spectra of spots, followed by single-factor optimization. Excellent agreement was obtained between predicted data and experimental results for a mixture of unknown pesticide intermediates. - J. Planar Chromatogr. 6, 6 6 69 (1993). Nat. Lab. Elem.-Org. Chem., Nankai Univ., Tianjin 300071 (RC) The possibilities of optical isomer separation by TLC on layers of chitin and its derivatives. J.K. R6zyto and I. Malinowska. Modified chitin layers can be used successfully for the separation of optical isomers of amino acids with ternary mobile phases containing methanol/water/aeetonitrile. Cu-modified chitin layers were advantageous ver Co and Ni layers for these kind of separations. The dependence of hRf values on the composition of binary and ternary mobile phases has been demonstrated. - J. Planar Chromatogr. 6, 3 4 - 3 7 (1993). Fac. Chem., M. Curie-Sktodowska-Univ., 20-031 Lublin (PL) Study of band broadening in enantioselective separations using microcrystalline cellulose triacetate. I. The linear case; IL Frontal analysis. S.C. Jacobson, A. Seidel-Morgenstern and G. Guiochon. The contributions of the mass transfer resistances to the band profile dispersion are analyzed especially the contribution of the adsorptiondesorption kinetics, as functions of these operating parameters. Linear chromatographic data were obtained for the enantiomers of Tr6ger's base separated on microcrystalline cellulose triacetate with pure ethanol as the mobile phase. The experimental elution profiles are compared with calculated profiles as a check on the quality of the efficiency measurements. Besides supplying information about the adsorption equilibrium, frontal analysis data can be used to determine kinetic parameters. Using the equilibrium-dispersive model of chromatography, the apparent axial dispersion coefficient was derived by fitting the breakthrough curve for each concentration step. The values are in general agreement with those obtained from the classical determination of the efficiency of elution profiles under linear conditions. The apparent dispersion coefficient determined from frontal analysis depends on the concen-

1 General analytical methods tration. - J. Chromatogr. 637, 1 3 - 2 8 (1993). Div. Anal. Chem., Nat. Lab., Oak Ridge, TN 37831-6142 (USA)

Planar chromatography coupled to mass spectrometry. K.L. Busch, J.O. Mullis and R.E. Carlson. In coupling TLC/MS techniques direct sputtering of most organic samples is more effective from aluminium-backed TLC sheets than from Empore chromatographic media. However, alkaloid samples can after derivatization be treated on Empore TLC plates by volatilization into an electron/chemical ionization source, development and concentration of thin-film fluorescent dyes for analysis by liquid secondary ion mass spectrometry (LSIMS), and the use of a CCD-based imaging system to explore the integration of optical and mass spectrometric information for the characterization of samples separated by thin layer chromatography. - J. Liquid Chromatogr. 16, 1695-1713 (1993). School Chem. Bioehem., Inst. Technol., Atlanta, GA 30332-0400 (USA) Partitioning and adsorption in gas-liquid-solid chromatography: Models of temporal moments for retention and variance. B J. McCoy. A mathematical based model is proposed to develop expressions for retention time and variance in linear gas-liquid-solid chromatography. Fundamental mass transfer models with adsorption and partitioning effects for solid chromatographic supports, covered with thin films of stationary liquid, based on mass-balance partial-differential equations, include the significant phenomena: convection, axial dispersion, gasliquid mass transfer, intraparticle diffusion, and liquid-solid adsorption. Expressions for retention time and band variance (first and second temporal moments) are presented and evaluated for four distinct models: (1) capillary tube with inner surface covered with a uniform-thickness liquid film, (2) column of nonporous spheres covered with a uniformthickness liquid film, (3) porous spherical particles with intraparticle pores covered with a uniform-thickness liquid film, (4) porous spherical particles with intraparticle pores completely filled with liquid. Chromatographia 36, 234-238 (1993). Dept. Chem. Engin., Univ. California, Davis, CA 95616 (USA) Stainless steel capillary columns for high temperature gas chromatography. Naizhong Zou, Tsui Yusheng, Sun Jiahe and Lu Wanzhen. Unlike fused silica capillary columns, stainless steel WCOT and PLOT columns can be operated at temperatures in excess of 400°C. High temperature simulated distillation has been performed successfully with a macro bore WCOT column and rapid PNA (paraffin, naphthene, and aromatic) analysis with a multidimensional gas solid chromatographic system using PLOT columns. - J. High Resol. Chromatogr. 16, 1 8 8 191 (1993). Res. Inst. Petroleum Processing, Beijing 100083 (RC) Application of dithiocarbamate resin-metal complexes as stationary phases in gas chromatography. Chia-Fu Yeh, Sun-Dsong Chyueh, Wei-Shi Chen, Jia-Der Fang and Chuen-Ying Liu. The complexing behaviour and the stability of a new chelating resin based on silica gel coupled to dithiocarbamate functional groups and silanes with diamino functional groups as spacers are investigated. The resin under optimum pH conditions formed a 1 : 1 metal complex with copper ion. The affinity of metal ions toward the synthesized resin decreased in the order Hg(II) > Cu(II) > Cd(II) > Zn(II). The resin exhibited efficient eomplexation of transition metal cations. The cadmium, copper and zinc complexes were investigated for application as stationary phase for the gas chromatographic analysis of dialkyl sulphides. Factors affecting the retention and sample selectivity were studied. A shorter retention time and sharp peaks were obtained when ammonia was introduced into the mobile phase. At an oven temperature of 100°C, a flow-rate of 60 ml rain -1 and use of a flame ionization detector, the analysis of dialkyl sulphides showed that the copper resin complex as the stationary phase gave the best results. - J. Chromatogr. 630, 275-285 (1993). Dept. Chem., Nat. Univ., Taipei (Taiwan) Enantiomer separation on amylose tris(n-butylcarbamate) by gas chromatography. V. Schurig, J. Zhu and V. Muschalek. The synthesis and chromatographic properties of seven aromatic and alkyl amylose and cellulose carbamates have been described as ehiral stationary phases in gas chromatography. Amylose tris(n-butyl-

1.1.3

Chromatographic methods

carbamate can be used for enantiomer separation. - Chromatographia 35, 237-242 (1993). Inst. Org. Chem., Univ., W-7400 Tiibingen (D) Separation of chiral silicon compounds using permethylated ~-,/~-, and ~cyclodextrin capillary GC columns. B. Feibush, C.L. Woolley and V. Mani. Permethylated ~-, ]3-, and ~/-cyclodextrin GC stationary phases were used to resolve racemic silane derivatives, R1R2Si*PhMe. Particularly good resolutions were obtained on the 7-CD phase for racemates containing a silanol group, R1 = OH. General influences of stationary phase on solute molecules are discussed. - Anal. Chem. 65, 1130 - 1133 (1993). Supelco, Inc., Supelco Park, Bellefonte, PA 16823 (USA) Pulsed-flame photometer: A novel gas chromatography detector. S. Cheskis, E. Atar and A. Amirav. A flame detector based on a pulsed-flame operation instead of the conventional continuous-flame mode is developed. The principle of this detector is that the combustible gas flow rate cannot sustain a continuous-flame so that the ignited flame propagates back to the combustible gas mixture source and is self-terminated after the combustible gas mixture is burnt. The continuous gas flow creates additional ignitions in a periodic fashion. The use of the PFPD as gas chromatographic detector is discussed. The main advantages of the PFPD include improved detection sensitivity for sulfur and phosphorus, much higher selectivity against hydrocarbon molecules, lower gas consumption, reduced emission quenching, additional temporal information, and the ability to detect selectively other heteroatoms such as nitrogen or the simultaneous detection of sulfur and carbon. - Anal. Chem. 65, 5 3 9 555 (1993). School Chem., Sackler Fac. Exact Sci., Univ., Tel Aviv 69978 (IL) Multidimensional gas chromatography with parallel cryogenic traps. N. Ragunathan, K.A. Krock and C.L. Wilkins. The incorporation of parallel cryogenic traps between a first stage GC precolumn and a second stage GC analytical column is proposed. Such an arrangement can be successfully adapted to the separation of complex mixtures as gasoline samples by GC-GC-IR-MS systems. Following a preliminary separation, using only the first column, a second portion of the same sample is injected for GC-GC analysis. Heart cuts from four different segments of the chromatogram identified in the preliminary separation are analyzed using an analytical column of different selectivity. These results demonstrate significantly enhanced chromatographic resolution using chromatographic conditions permitting joint use of information-rich infrared and mass spectral detectors. Thus, it is suggested that MDGC systems employing more than two parallel cryogenic traps and multiple analytical GC columns could be useful. - Anal. Chem. 65, 1012 - 1016 (1993). Dept. Chem., Univ. Calif., Riverside, CA92521 (USA) Potential and limitations of differently designed programmed-temperature injector liners for large volume sample introduction in capillary GC. J. Staniewski and J.A. Rijks. Programmed temperature sample introduction is an attractive technique both for the introduction of large volumes (up to 1000 gl) of dilute samples in capillary gas chromatography and for LC-GC interfacing. A new type of liner containing a porous bed of sintered glass is introduced. Solute recoveries achieved with this liner are compared with those obtained from liners packed with Tenax TA and Thermotrap TA. An open liner containing baffles and a small plug of silanized glass wool in its upper section was used as a reference. The maximum speed of sample introduction allowable using the new liner is ca one order of magnitude higher than for the standard liner. Liners packed with trapping materials such as Tenax TA or Thermotrap TA also provide significantly improved trapping efficiencies, even when used at relatively high temperatures. J. High Resol. Chromatogr. 16, 182 187 (1993). Poznafi Techn. Univ., Inst. Chem. Technol., Engin., 60-965 Poznafi (PL) A 3 pm polymeric packing material for gel permeation chromatography. E. Meehan and S. Oakley. The properties of a 3-gin crosslinked polystyrene-divinylbenzene GPC packing materials are presented. The packing has a molecular weight

161 resolving range as high as 30,000 Da and, therefore, is particularly suitable for the analysis of low molecular weight components, particularly if the samples contain oligomeric components. The high efficiency of the columns can only be fully realised when system parameters such as dead volume, sample loading and eluent flow rate are optimized. The particle size also appears suitable for high efficiency separations over a large dynamic range by using combined hydrodynamic chromatography/ GPC mechanisms. - LC-GC Intern. 5, 3 2 - 3 7 (1993). Polymer Labs., Church Stretton, Shropshire (GB) Microcolumn size exclusion chromatography with polymeric stationary phases. H.J. Cortes and C.D. Pfeiffer. The preparation of highly efficient microcolumns for size exclusion chromatography (micro SEC) with polymer packings of 50- and 1000A pore size is studied. Short columns (30 cm) should be prepared at 400 atm with high slurry concentrations while long columns (1 m) are best prepared at low packing pressures with dilute slurries. Columns with 75 000 plates/m can be routinely prepared. Resolution factors obtained (D~) were 0.033 for a conventional size column, 0.017 for 1-m microcolumns operated at the optimum linear velocity; and 0.021 for the microcolumns operated at a linear velocity chosen to yield retention times equivalent to the conventional size column. The results obtained indicate better performance for the micro SEC system when compared to conventional size SEC. - Anal. Chem. 65, 1476-1480 (1993). The Dow Chem. Comp., Anal. Sci., 1897B Building, Midland, MI 48667 (USA) A differential pressure capillary viscometer as a detector for size exclusion chromatography. S. Mori, T. Kawashima and M. Hamajima. A differential pressure capillary viscometer has been designed and the performance of the viscometer was evaluated. The viscometer was composed of four capillaries and two differential pressure transducers. The viscometer was connected to the size exclusion chromatography (SEC) system. The first capillary was connected before and the second after the sample column, the third and the fourth after the reference column. An empty tubing used as a delay reservoir was connected between the third and the fourth capillary. The differential pressure between the inlets of the second and the fourth capillary was measured. The other two capillaries were used for the flow compensation. The linear relationship was obtained between log intrinsic viscosity and log molecular weight (MW) for polystyrenes over the MW ranging from 104 to 106. The upward deviation from the linearity for the polymers with MW lower than 104 and the downward deviation for those higher than 106 were observed. - Bunseki Kagaku 42, 3 9 - 4 4 (]993); (Orig. Jap.) Fac. Eng., Mie Univ., Mie 514 (J) Transverse flow gating interface for the coupling of microcolumn LC with capillary zone electrophoresis (CZE) in a comprehensive two-dimensional system. A.V. Lemmo and J.W. Jorgenson. A 2D system is presented which couples microcolumn size exclusion chromatography (SEC) with CZE for the separation of proteins. A new interface design is used to couple SEC, carried out in packed capillary columns of 250- and 100-gin inner diameters, together with CZE. This interface design uses a transverse flow of CZE buffer to prevent SEC column effluent from being electroinjected onto the CZE capillary until an injection is desired. This interface provides reproducible CZE injections while introducing minimal extracolumn band broadening into the system. The 2D system is completely automated under computer control. - Anal. Chem. 65, 1576-- 1581 (1993). Dept. Chem., Univ., Chapel Hill, NC 27599-3290 (USA) Modern countercurrent chromatography. D. Thi6baut and R. Rosset. The two modern countercurrent chromatography techniques, high speed countercurrent chromatography and cerrtrifugal droplet countercurrent chromatography are described. In the high speed version of this technique a coil planet centrifuge type apparatus is used and in the centrifugal droplet technique a centrifugal partition chromatograph. The techniques are mainly useful in semipreparative and preparative chromatography. Analytical countercurrent chromatography apparatus consist of columns with a column ranging from 15 ml for high speed countercurrent chromatography and up to 200 ml for centrifugal droplet

162

1 General analytical methods

countercurrent chromatography. Microgram to gram amounts of a sample can be separated in 15 - 30 rain to several hours. The basic theory of the method is reviewed as well as the instrumentation, the operation and possibilities of application. (50 References) - LC-GC Intl. 6, 1 5 4 162 (1993). Anal. Chem. Lab., Ecole Sup. Phys. Chim. Ind., F-75231 Paris Cedex 5

1.1.4

Electrochemical methods

4th European Conference on Electroanalysis (ESEAC '92). Noordwijkerhout, May 31 - June 3, 1992. 180 persons attended this conference and more than 130 contributions were given from participants from more than 30 countries. A large number of the presented papers have now been published in Anal. Chim. Acta. They cover developments in stripping voltammetry, new electroanalytical techniques like the use and development of microelectrodes and even ultramicroelectrodes, biosensors and chemically modified electrodes, and the wide field of environmental, pharmaceutical and biomedical applications as well as the use of electrochemical detection in flow analysis and chromatography. Some special problems encountered with electroanalysis like the use of chemometric methods and the application of electroanalytical methods for special matrices are shown in the chapter micellaneous. - Anal. Chim. Acta 273, 3 - 566 (1993). 8th International Symposium on Capillary Eleetrophoresis and Isotachophoresis. Rom, October 6 - 9 , 1992. 30 of the Lectures and Posters presented at this meeting from over 160 participants from 14 European Countries, Japan, Canada and the USA are now published in Journal of Chromatography. The priorities of the 1992 conference were theory, new equipment, application in inorganic, organic, pharmaceutical and clinical chemistry. But new fields of application like for example the determination of explosives in soil are included as well. Special attention was given to the coupling of capillary isotachophoresis and capillary zone electrophoresis. A theoretical description of the electrolyte systems that can be used in the on-line combination of the two methods and the necessary sample pretreatment are given. -- J. Chromatogr. 638, 117-373 (1993). 2nd International Symposium on Capillary Electrophoresis. York (UK), August 2 6 - 28, 1992. 20 of the Lectures and Posters presented at this meeting are now published in Journal of Chromatography. Most of the publications deal with the possibilities of electrophoresis for clinical and pharmaceutical problems. But beside this the coupling of capillary electrophoresis and mass spectrometry as well as methodical and instrumental aspects of the quantitative capillary electrophoresis and the diode-laser based indirect absorption detector and finally theoretical aspects like the manipulation of electroosmotic flow are covered. -- J. Chromatogr. 636, 3 - 186 (1993). A new type of pH- and detergent-stable coating for elimination of electroendosmosis and adsorption in (capillary) electrophoresis. S. Hjert~n and K. Kubo. To eliminate electroendosmosis and solute adsorption on the tube wall fused silica, quartz, or glass electrophoresis tubes have been coated with hydrophilic polymers, such as methyl cellulose or dextran. The coating was not split off upon exposure to a 5% solution of sodium dodecyl sulfate (SDS) at pH around 12 during a period of sixteen days or to 0.5 M HC1 (pH 0.3) during 10 days. The high stability of the coating, which is attached to the silica surface via Si-O-Si-C bonds, permits electrophoresis experiments at extreme (besides neutral) pH values and allows short washes of the electrophoresis tubes between the runs with 0.05 M sodium hydroxide (pH 12.7) containing 5% SDS, and with 1 M HC1, which release efficiently those solutes which have a tendency to adsorb onto the coating. The quality of the coating was strongly affected by their surface structure. - Electrophoresis 14, 390--395 (1993). Dept. Biochem., Univ., Uppsala (S)

Essential peak area normalisation for quantitative impurity content determination by capillary electrophoresis. K.D. Altria. The necessity of normalization of peak areas with migration times in CE prior to reporting impurity level results as %area to area is confirmed. The impact of normalisation on %area/area results was demonstrated using the pharmaceutical ranitidine, and a synthetic precursor, as test solutes. The UV absorbance of each compound was determined and found to be equivalent. A solution of ranitidine hydrochloride was then spiked with a weighed amount of precursor. The %area/area CE results, when normalised, matched the known weighed ratio. Use of uncorrected peak area data in this instance would have resulted in a severe underestimation of impurity levels. - Chromatographia 35, 177-182 (1993). Pharm. Anal., Glaxo Group Res., Ware, Herts. (GB) Suppressed eonduetometric capillary electrophoresis separation systems. P.K. Dasgupta and L. Bao. Ion-exchange based suppression and conductometric detection are combined with capillary electrophoresis. A tubular cation-exchange membrane is installed at the end of a 60-era-long 75-gm-bore fusedsilica capillary. A static dilute acid regenerant solution surrounds the membrane that functions as a suppressor. With positive high voltage applied to the capillary inlet and the regenerated solution grounded, effective suppression of electrolytes such as solutions of alkali metal borate, glycinate, or cyanide is observed. Electroosmotic flow carries the capillary effluent past the suppressor into a conductivity detection cell constituted by two platinum wires inserted through the wall of a poly(vinyl chloride) capillary. The system provides detection limits in the 1 0 - 2 0 gg/1 range for a variety of anions; a typical separation requires t 5 min. Applicability to a variety of real samples is demonstrated. Determination of ions without useful optical absorption is achieved. - Anal. Chem. 65, 1003 - 1011 (1993). Dept. Chem. Biochem, Texas Tech Univ., Lubbock, TX-79409-1061 (USA) On the pH hysteresis of electroosmotic mobility with capillary zone electrophoresis in silica capillary. T.-L. Huang. A porous gel model of the silica-solution interface is given to explain the pH hysteresis effect on the electroosmotic mobility in capillary zone electrophoresis with silica capillaries. - Chromatographia 35, 395 - 398 (1993). 105D Rock Glen Rd., Baltimore, MD 21229 (USA) Use of a microemulsion system to incorporate a lipophilic chiral selector in electroldnetic capillary chromatography. J.H. Aiken and C.W. Huie. Good chiral separation of (1R, 2S) and (1S, 2R)-ephedrine using microemulsion electrokinetic capillary chromatography is reported. The lipophilic chiral selector, (2R, 3R)-di-n-butyl tartrate (0.5% w/w), was introduced into the electrophoretic buffer consisting of 0.6% (w/w) sodium dodecyl sulfate (SDS) and 1.2% (w/w) 1-butanol in 15 mM trishydroxyaminomethane buffer (pH 8.1). The two isomers of ephedrine were separated with excellent resolution. - Chromatographia 35, 4 4 8 450 (1993). Dept. Chem., State Univ., Binghamton, NY 13902-6000 (USA) Planar glass chips for capillary eleetrophoresis: repetitive sample injection, quantitation, and separation efficiency. K. Seiler, D.J. Harrison and A. Manz. Miniaturization is going on. An electrophoresis device of 14.8 cm x 3.9 c m x 1 cm on a planar glass substrate is described which includes a sample injection system and a capillary electrophoresis channel integrated together. Voltages of at least 25 kV may be applied over an 11cm-long capillary channel with sufficient dissipation of the Joule heat generated (1.8 W/m). The glass substrate sustains at least 105 V/cm dc without dielectric breakdown. Using laser-induced fluorescence detection, mixtures of fluorescein derivatives and fluorescein isothiocyanatelabeled amino acids were injected and separated. Up to i 00 000 theoretical plates and ~ 20 plates/V were obtained under optimized conditions, comparable to results with fused-silica capillaries. - Anal. Chem. 65, 1481-1488 (1993). Dept. Chem., Univ. Alberta, Edmonton, Alberta T6G 2G2 (CDN) Determination of cations and anions by capillary electrophoresis combined with suppressed conductivity detection. N. Avdalovic, C.A. Pohl, R.D. Rocklin and J.R. Stillian.

1.1.4

Electrochemical methods

The possibilities of using suppressed conductivity detection in capillary electrophoresis of inorganic and organic ions are elucidated. Using direct injection techniques (no electrostacking), minimum detection limits for common organic and inorganic ions are in the range of 1 - 10 ppb. Suppressors are made from short ion-exchange membrane capillaries and are placed between the separation capillary and the detector cell. The suppressor is placed in the destination vial, which contains regenerant and the ground electrode. The method is dependent on the presence of electroendoosmotic flow in the capillary to transport analyte and buffer ions through the suppressor. 13 common inorganic anions can be separated in 21 rain with this method. - Anal. Chem. 65, 14701475 (1993). Dionex Corp., 1228 Titan Way, Sunnyvale, CA 94088 (USA) Enantiomer separation by electrochromatography in open tubular columns coated with CHIRASIL-DEX. S. Mayer and V. Schurig. A chiral surface in capillary electrophoresis is capable to induce chiral recognition towards racemic solutes. The possibility of chiral interactions in a 50 gm i.d. open tubular column was created by coating the inner surface with an immobilizable dimethylpolysiloxane containing chemically bonded permethylated [3- or 7-cyclodextrin (CHIRASIL-DEX). This chiral stationary phase was employed for the separation of the enantiomers of non-steroidal antiinflammatory drugs and small molecules by the principle of electrochromatography under various conditions. Parameters affecting enantiomer separation by electrochromatography have been evaluated. - J. Liquid Chromatogr. 16, 915-931 (1993). Inst. Org. Chem., Univ., W-7400 Tiibingen (D) Effect of rotation rate on the response at poly(chlorotrifluoroethylene) composite disk electrodes. J.E. Vitt, D.C. Johnson and D.E. Tallman. The effect of rotation rate on the voltammetric response has been investigated with microelectrode arrays operating as rotating disk electrodes (RDEs). The microelectrode array RDEs were Kelgraf (graphite and KeI-F) and Au/Kelgraf (Au, graphite, and KeI-F) composite electrodes. A significant enhancement in current density was observed in comparison to solid RDEs. The relative current density (3) was defined as the ratio of the current density at a microelectrode array RDE in comparison to that at a solid RDE. The largest values of Jwere obtained for the lowest values of rotation rate and for ca. 2 - 3 % active area; however, the values of J were dependent on the choice of the test reaction. - Anal. Chem. 65, 231-237 (1993). Dept. Chem., Ames Lab., Iowa State Univ., Ames, IA 50011 (USA) Interdigital capacitance and surface acoustic wave (SAW) sensors. D.C. Stone and M. Thompson. Different mechanisms by which a surface film can affect SAW sensor response are presented. The effect of the water content of sample vapors on the dielectric constant of a surface film on SAW sensors is examined with respect to signal noise and the electrical properties of the interdigital transducer (IDT) electrodes. The total static capacitance of an IDT is described theoretically, and effects of discrepancies in published equations are discussed. - Anal. Chem. 65, 352-362 (1993). Dept. Chem., Univ. Toronto, Ontario M5S 1A1 (CDN) Separation of cresols using coelectroosmotic capillary electrophoresis. S.M. Masselter, A.J. Zemann and O. Bobleter. The positionaI cresol isomers can be separated using the new method coelectroosmotic capillary electrophoresis. By applying a high voltage with negative polarity, the sample anions migrate in front of the electroosmotic flow marker. In this way the times of analysis are shorter compared to counterelectroosmotic CE methods. Reversion of the electroosmotic flow was carried out by a polycationic ammonium compound. The separations were carried out at high pH values (pH 12) to obtain complete dissociaton of the cresols and short times of analysis (less than 5 min) through fast migration of the cresol towards the anode. Various aliphatic alcohols were added to improve peak shape and resolution. - Electrophoresis 14, 36 - 39 (1993). Inst. Radiochemie, LeopoldFranzens-Univ., A-6020 Innsbruck Improved method for end-column amperometric detection for capillary electrophoresis. S. Sloss and A.G. Ewing.

163 The coulometric efficiency is discussed obtained for end-column amperometric detection in capillary electrophoresis (CE) in 2- and 5-gin i.d. capillaries using l l - p m diameter carbon fiber microelectrodes. The coulometric efficiency depends strongly on the alignment of the capillary and the electrode. An improved design for end-column detection in CE is also presented. This new design involves etching the detector end of the capillary so that alignment of the capillary bore and the electrode is easily maintained. Optimized end-column detection provides detection limits as low as 11 amol with peak efficiencies of 140000 theoretical plates for catechol. - Anal. Chem. 65, 577-581 (1993). 152 Davey Lab., Dept. Chem., The Penn. State Univ., University Park, PA-16802 (USA) Multiplexed fluorescence detector for capillary electrophoresis using axial optical fiber illumination. J.A. Taylor and E.A. Yeung. The axial beam excitation scheme for capillary electrophoresis described by the authors in Anal. Chem. 64, 1741 (1992) is used to simultaneously monitoring 10 capillaries undergoing electrophoresis. This provides a truly paralM multiplexing scheme for monitoring large arrays of capillaries. The system has no moving parts. Data rates are compatible. - Anal. Chem. 65, 956 - 9 6 0 (1993). Ames Lab.-USDOE and Dept. Chem., Iowa State Univ., Ames, IA 50011 (USA) Effect of sample stacking on resolution, calibration graphs and pH in capillary zone electrophoresis. J.L. Beckers and M.T. Ackermans. The effect of sample stacking on resolution, calibration graphs and pH shifts with the injection of long sampling zones at low concentrations is studied. Sample stacking can lead to an increase in the electroosmotic flow and extra peak broadening during the analysis, through which the gain in resolution will be lost. Further, the presence of different electrolytes in the capillary can cause pH shifts. A model is given for the calculation of migration times of components applying sample stacking. - J. Chromatogr. 629, 371 - 3 7 8 (1993). Lab. Instrum. Anal., Univ. Technol., 5600 MB Eindhoven (NL) Flow control in capillary zone electrophoresis by using a variable pressure - A system with versatile possibilities. K. B~ichmann, B. G6ttlicher, I. Haag and M. Hannina. The use of pressure as an universal flow control (lowering, elimination, reversal of the flow) in capillary zone electrophoresis is demonstrated for the separation of 10 phenols. The change of flow velocity is done for electrokinetic injection and electrostacking and it is limited by time. For increasing the velocity of simple separations it is possible to change pressure with time or to use constant pressure throughout the whole analysis. The influence of the pressure on the resolution and the applicability of the system for other separation problem is discussed. - GIT Fachz. Lab. 37, 514-522 (1993). FB Chemic, TH Darmstadt, W-6100 Darmstadt (D) Optimization of pH for the separation of organic acids in capillary zone electrophoresis. S.C. Smith and M.G. Khaledi. The usefulness of a mathematical model which describes the variation of the mobility of a solute as a function ofpH is discussed. The migration behavior and optimum separation of a set of substituted phenols is predicted. The resolution between each peak pair was calculated, and a window diagram of minimum resolution as a function of pH was employed in determining the optimum pH. - Anal. Chem. 65, 1 9 3 198 (1993). Dept. Chem., North Carolina State Univ., Raleigh, N.C. 27695-8204 (USA) On-column detection in capillary zone electrophoresis with ion-selective microelectrodes in conical capillary apertures. A. Nann and W. Simon. Drift and noise in CZE with an ion-selective microelectrode (ISME) as detector in an on-column position can be drastically reduced by etching the detector-side capillary end with hydrofluoric acid to a conical aperture. The field strength at the tip of the ISME is considerably reduced compared with that of the remaining capillary. - J. Chromatogr. 633, 207-211 (1993). Dept. Org. Chem., Swiss Fed. Inst. Technol. (ETH), CH-8092 Zurich Peroxyoxalate chemiluminescence (PO-CL)detection in capillary electrophoresis (CE). Nian Wu and C.W. Huie.

164

1 General analytical methods

The applicability of PO-CL for the post-column detection after CE separation followed by elutiou under pressure is investigated. Potential problems associated with incompatibilities between mixed aqueous-organic solvent and electrically driven separation systems were avoided by switching off the CE power supply at an appropriate time and connecting the CE capillary to a syringe pump to effect dynamic elution. The effects of dynamic flow-rate and PO-CL reagent concentration on the CL signal intensity and/or peak width were examined for the measurements of three dansylated amino acids. The average limit of detection for these analytes using this PO-CL method is about 1.2 fmol (ca. 85 nM) which is approximately 35-fold lower than UV absorption methods. - J. Chromatogr. 634, 309-3•5 (1993). Dept. Chem., Univ., Binghamton, NY •3902-6000 (USA)

Kalman filter-optimized simulation for step voltammetry. R.S. Bear, Jr. and S.D. Brown. A generalized method for simulating the voltammetric response of a heterogeneous electron-transfer reaction to a potential-step sequence is presented. By coupling the simulation with an extended Kalman filter, a recursive optimization of the simulation is performed to fit experimental data. Estimates of the heterogenous charge-transfer parameters are obtained in a single pass through the simulation. The reductions of Cr(H20)63+ in 0.5 M NaC104-0.0J M HC104 and Zn(II) in 1.0 M KNO3 are presented as example applications. Corrections for doublelayer effects were built into the simulation model. - Anal. Chem. 65, 1061-1068 (1993). Dept. Chem., Biochcm., Univ. Delaware, Newark, DE 19716 (USA)

Analysis of a dilute sample by capillary zone electrophoresis with isotachophoretic preconcentration. T. Hirokawa, A. Ohmori and Y. Kiso. A new apparatus was constructed for the combination of CZE and on-line ITP. A septum-type injector was used with a coupled column (0.5 and 0.25 mm i.D.). The concentration and volume of the test mixture injected by using a microsyringe were in the range of 166 - 1.66 gM and 0 . 5 - 50 gl, respectively. The ratio of the sample volume to the separation column volume (27 gl) was in the range 1.9-•85%. Although the migration time in the CZE stage did not change when ITP preconcentration was utilized, if the latter was not used the migration time was prolonged up to 400% nonqinearly to the above ratio. The utility of ITP-CZE for the determination of trace components in a matrix was also demonstrated. - J. Chromatogr. 634, 101-106 (•993). Appl. Phys., Chem., Fac. Engin., Univ., Higashi-hiroshima 724 (J)

Application of square wave voltammetry to strongly adsorbed quasireversible redox molecules. J.H. Reeves, S. Song and E.F. Bowden. A theory to calculate the square wave voltammetric response of strongly adsorbed quasireversible redox molecules (Ox + ne- = Red) is described. Theoretical voltammograms were calculated based on the following assumptions: (1) stable redox states; (2) monolayer or less surface coverage; (3) equivalent surface sites and adsorbates; (4) no adsorbate-adsorbate interactions; (5) no diffusional contributions to the current; and (6) Butler-Volmer electrode kinetics. A working curve strategy based on peak separation between positive-scan and negativescan net current voltammograms was developed to facilitate the semiquantitative determination of electron transfer rate constants. The utility of the approach was demonstrated by the successful prediction of voltamograms of adsorbed cytochrome c on 16-mercaptohexadecanoic acid monolayer electrodes. - Anal. Chem. 65, 683-688 (1993). Dept. Chem., Univ. North Carolina, Wilmington, NC 28409 (USA)

Diode laser-based concentration gradient detector for detection of capillary isoelectric focusing. Jiaqi Wu, P. Frank and J. Pawliszyn. A diode laser-based concentration gradient detector was used in a compact capillary isoelectric focusing (CIEF) instrument which also includes a short piece of 20-pm-i.d. capillary and which can be used with capillaries narrower than 50 gin. The diode laser was mounted with a focusing lens and driving circuit in an 8-cm-long, 2-cm-diameter aluminium barrel, and was powered by a 9-V battery. Optical geometry of the detector was optimized. The detection limit in concentration for ovalbumin reaches 2.0 x 10-7 M. This on-column detection limit of the universal detector is within the same order of magnitude as that of a diode laser-based fluorescence CE detector. The resolution of the instrument is about 0.02 pH units. - Appl. Spectrosc. 46, 1837-1840 (1993). Dept. Chem., Univ., Waterloo, Ontario N2L 3G1 (CDN) Capillary isoeleetric focusing (C|EF) with imaging detection. Jiaqi Wu and J. Pawliszyn. A simple on-line absorbance imaging detector for CIEF is described. Separation and detection of protein samples could be completed in 2 rain. The use of the imaging detection system also allowed for studying the focusing process. When a 4 cm long, 200-pro i.d. square capillary was used as the separation column, the concentration detection limit of the detector reached 5 pg/ml. - J. Liquid Chromatogr. 16, 1891 -1902 (•993). Dept. Chem., Univ., Waterloo, Ontario N2L 3GI (CDN) Bidirectional isotachophoresis. I. Verification of bidirectional isotachophoresis and simultaneous determination of anionic and cationic components. T. Hirokawa, K. Watanabe, Y. Yokota and Y. Kiso. The phenomenon of bidirectional isotachophoretic migration was confirmed by the direct measurement of the pH profiles and the boundary velocities of the separated zones. The anolyte used was 10 mM HC1[3-alanine (pH 3.6) and the catholyte was 10 mM KOH-acetic acid (pH 4.8). Bidirectional isotachophoresis could be achieved with an electrolyte system consisting of a leading electrolyte for an anionic analysis and one for a cationic analysis. The combination was not arbitrary but the pH difference between the anolyte and the catholyte was restricted to keep the effective mobility of the terminating ion not too small. The simultaneous separation and determination of anions and cations in a test mixture were demonstrated. - J. Chromatogr. 633, 251-259 (•993). Appl. Phys., Chem., Fac. Engin., Hiroshima Univ., Higashi-hiroshima 724 (J)

Triple-pulse voltammetry and polarography. C. Serna, A. Molina, L. Camacho and J.J. Ruiz. The solution of the faradaic response of a slow electron transfer to a triple pulse of potentials was derived for planar approximations of a static mercury drop electrode and the dropping mercury electrode. The effects of the formation of the double layer have not been taken into account in the mathematical treatment. The solution obtained was verified by comparising of the solution to experimentally measured i-t curves for some completely reversible, completely irreversible, and quasi-reversible processes, namely the reduction of Cd(II), Cr(III), and Zn(II), respectively. The use of a triple pulse of potentials to develop new voltammetric and polarographic techniques, improving on the performance of double-pulse techniques, is discussed. - Anal. Chem. 65, 215-222 (•993). Dept. Quim. Fis., Fac. Cien. Quire. Mat., Univ. de Murcia, E30Â00 Murcia (E) A computer-controlled measuring device for staircase-voltammetry. H.-J. Haase. A computer-controlled measuring device for use in stair-case voltammetry is described. Examples of analysis show the ability of this measuring device. The standard deviation of the measured values lies in the lower ppb range ( 2 - 6 ppb). With a ] 0 min electrolytical enrichment a detection limit of 0.1 ppb can be reached. - GIT Fachz. Lab. 37, 440-446 (1993). Halbleiterwerk Analytik, Siemens AG, W-8400 Regensburg (D)

1.1.5

Miscellaneous methods, reagents, sampling

Application of an electrothermal vaporization unit for trace analysis. A. Golloch, M. Haveresch-Kock and W.G. Fischer. The possibilities of the direct analysis of solid samples by means of an electrothermal vaporization (ETV) unit for sample introduction into an ICP is described. This new ETV-unit is based on disposable graphite cups with a volume of 500 or 700 gl. The sample cup is placed on a graphite bridge located between two copper electrodes. The bridge can be heated in steps up to 2800 K. A direct coupling with the ICP is provided. The systems seems valuable in environmental analysis. - GIT

1.1.6

Data processing, chemometry, statistics

Fachz. Lab. 37, 9 1 - 9 6 (1993). Univ./FH Duisburg, Fachb. 6, Lotharstr. 1, W-4100 Duisburg (D) Analyses of cryogenic samples using ion-induced desorption and multiphoton resonance ionization. M.H. Ervin, M.C. Wood and N. Winograd. The feasibility of characterizing ion-desorbed neutral molecules dissolved in frozen liquid matrices by ion-beam-induced desorption with multiphoton resonance ionization detection is demonstrated. The timeof-flight mass spectrum, obtained in this way for a millimolar tryptophan/H20 solution, is virtually identical to that for a submonolayer of tryptophan on a silicon wafer. A detection limit of 2 x 10 6 M is demonstrated. Since ion beam samples have approximately one layer of 0.1 cm 2 and 10 is molecules/era2 of ice, this concentration corresponds to approximately 4× 106 molecules/layer. The signal exhibits an exponential decay with primary ion dose due to the accumulation of primary ion damage in the near-surface molecules. Frozen aqueous solutions can simulate biological matrices. - Anal. Chem. 65, 417-420 (1993). 152 Davey Lab., Dept. Chem., The Penns. State Univ., University Park, PA 16802 (USA) Solventless collection of analytes by rapid depressurization after static supercritical fluid extraction. D.J. Miller, S.B. Hawthorne and M.E.P. McNally. To collect analytes from SFE without any flow restrictor a method is developed which uses an empty collection vial. Following static SFE, the analytes are collected by rapidly ( 3 - 30 s) depressurizing the CO2 effluent through a 178-p,m i.d. stainless steel tube into a capped screw-top vial. The effects of different trapping parameters on collection efficiencies including vial configuration, exit tube inside diameter, extraction temperature, analyte volatility, and collection time were investigated. Collection efficiencies of analytes as volatile as n-heptane are quantitative ( > 95%), and wet samples showed no evidence of restrictor plugging in contrast to the plugging associated with the SFE of wet samples when small i.d. flow restrictors are used. Solventless collection of PCBs, PAHs, gasoline, and diesel fuel by SFE generally showed high ( > 90%) collection efficiencies, and recoveries normally exceed those obtained using dynamic SFE with collection in a liquid solvent. - Anal. Chem. 65, 1038-1042 (1993). Energy, Environ. Res. Cent., Univ., Grand Forks, ND 58202-9018 (USA)

1.1.6

Data processing, ehemometry, statistics

5th International Conference on Chemometrics in Analytical Chemistry. Montreal (Canada), July 14-17, 1992 (CAC'92). Virtualiy all presentations given on this conference have been converted into manuscripts which have now been published in Analytica Chimica Acta. The meeting was an effort to show the importance of the use of statistical and mathematical methods to extract information out of chemical data. This is still not fully accepted and it should be an integral part of chemical education. The following parts are covered by the publications: General Applications of Chemometrics, Modelling, Neural Networks, Application in Analytical Spectroscopy, Chromatography and Environmental Analysis, Expert Systems, Application to Mixture Analysis. - Anal. China. Acta 277, 165-510 (1993). Estimation of performance characteristics of an analytical method using the data set of the calibration experiment. L. Cuadros Rodriguez, A.M. Garcia Campafia, C. Jim~nez Linares and M. Romfin Ceba. The application of a statistical linear regression model for the calculation of the equation of the calibration line is described in order to estimate the performance characteristic of an analytical method. This model calculates the analytical sensitivity, limit of detection, limit of determination and precision of a method of instrumental analysis through a data set obtained by calibration experiments and has been applied to spectrophotometric, spectroflnorimetric and chromatographic methods. The values obtained are independent of the instrument used and can be applied as a criterion of comparison between different methods proposed for the same analyte. These characteristics have been

165 calculated using the IUPAC suggested model as well and the results have been compared. - Anal. Lett. 26, 1243-1258 (1993). Dept. Anal. Chem., Fac. Sci., Univ., 18071 Granada (E) Comparison of different calibration methods suited for calibration problems with many variables. H. Holst. Different kinds of statistical methods proposed in the literature as suited for solving calibration problems with many variables are compared. These are: principal component regression, partial least-squares, and ridge regression. The statistical techniques themselves do not provide robust results in the spirit of calibration equations which can last for long periods. A way of obtaining this property is by smoothing and differentiating the data. The principle is applied to data from a soybean feedingstuff industry. - Appl. Spectrosc. 46, 1780-1784 (1992). Inst. Math. Statistics, Operations Res., Techn. Univ. Denmark, DK-2800 Lyngby A test for the simultaneous detection of two outliers among extreme values of small data sets. C.E. Efstathiou. For the simultaneous detection of two outliers among extreme values of small data sets a simple test is developed which is analogous to Dixon's classic Q-test. It is based on the probability distribution of the product of two Qexp values (QP: quotient product). Each Qexv value is calculated from the data set considering the presence of one and ignoring the presence of the other suspect value. Critical QP-values, calculated by a stochastic (a Monte-Carlo) procedure, are given for data sets containing 5 to 16 observations (replicates) at 0.90, 0.95, and 0.99 confidence levels. Based on the same principle, tests for the simultaneous detection of more than two outliers can be readily designed. It can be incorporated in software packages for data treatment. - Anal. Letters 26, 3 7 9 - 390 (1993), Lab. Anal. Chem., Univ. Athens, Athens 15771 (GR) Fluorometric data processing strategies using nanosecond waveform digitizers. T.L. Campos and F.E. Lytle. Nanosecond fluorometric data are digitized and transferred to a microcomputer after each excitation pulse, then processed by a software module simulating either analog or photon counting detection. Software anode current processing provides display of the decay and integration of its area in the same operation, offers a multiplex advantage to improve decay collection rate, and allows the definition of a nearly rectangular gating function with sharp 1-ns edges. Application of the photon counting method to fluorometric instruments based on low-repetitionrate lasers is achieved with a multistop~ multilevel discrimination algorithm to increase the usable detection rate. The ability to achieve photon counting detection permits a more rigorous statistical treatment of the data and can provide transit time-spread limited resolution. - Appl. Spectrosc. 46, 1859-1865 (1992). Dept. Chem., Purdue Univ., West Lafayette, IN 47907 (USA) Use of artificial neural networks for the classification of vegetable oils after GC analysis. R.A. Francelin, F.A.C. Gomide and F.M. Lan~as. Three artificial neural networks are proposed for the classification of vegetable oils submitted to GC analysis through their FAME profiles: the Hopfield model as a content-addressable memory (CAM), the Hamming model and the multi-layer perceptron. A brief description of these nets is presented and further implemented for the classification of known vegetable oils. After the learning step, unknown samples are presented to the nets and the identification step performed. The Hamming net gave the best performance being able to learn all oils and classifying correctly the unknown inputs applied to it. For the multilayer perceptron a proper recodification was achieved. The Hopfield net has shown satisfactory behaviour although there are important 1imitations. - Chromatographia 35, 160-166 (1993). ICMSC-Univ. S~o Paulo, 13560 Sgo Carlos-SP (BR) Practical implementation of neural networks for the interpretation of infrared spectra. Q.C. van Est, P.J. Schoenmakers, J.R.M. Smits and W.P.M. Nijssen. The feasibility of applying networks for the interpretation of Fourier transform infrared spectra in practice is demonstrated. An implemen-

166 tation of a modular system of networks, that can easily be expanded and is user friendly, is described. The present application allows the spectroscopist to consult neural network modules to obtain information on the presence or absence of functional groups. A few examples are described. - Vibr. Spectrosc. 4, 263-272 (1993). Philips Res. Lab., 5600 JA Eindhoven (NL)

Nonlinear fitting by using a neural net algorithm. Zheng Li, Zhaonian Chang, Li Xu and Tonghua Li. An artificial neural network is described which provides a unified form for nonlinear fitting. This novel transfer function is very suitable for normalized data set and converges much faster. The overfitting problem is discussed in detail. The optimal fitting model can be obtained by adjusting the number of hidden nodes. A data set of furnace lining durability was used as an example to demonstrate the method. The predictive results were better then that of principal component regression and partial least square regression. - Anal. Chem. 65, 393 - 3 9 6 (1993). Lab. Comp. Chem., Shanghai Inst. Organ. Chem., Acad. Sin., Shanghai (RC) Analysis of correlated spectral data. I. Scarminio and M. Kubista. A program for analyzing correlated spectral data by Procrustes rotation, which eliminates the need for reference samples (Kubista, M. Chem. Intel. Lab. Syst. 1990 7, 273) is described. The experimental spectra are the only "input" required by the DATa ANalysis (DATAN) program, which calculates the number of components, their spectral profiles, their concentrations, and the ratio of their responses to two spectroscopic measurements. The DATAN program first calculates common score and loading vectors to the two data sets by the NIPALS algorithm, and the number of spectroscopically independent components is determined by a Z2 test. The score matrices for the two measurements are then related through Procrustes rotation, which gives the spectral profiles of the components, their concentrations in the samples, and the ratios between their responses to the two measurements. The program is available by the authors. - Anal. Chem. 65, 409-416 (1993). Dept. Phys. Chem., Chalmers Univ. Technol., S-41296 Gothenburg Analysis of first-order rate constant spectra with regularized least-squares and expectation maximization. 1. Theory and numerical characterization. B.J. Stanley, S.E. Bialkowski and D.B. Marshall. Three mathematical models are compared for the analysis ofparallel, first-order rate processes: 1. The method of expectation maximization (EM); 2. Adaptive choice for the regularization parameters (CONTIN) and 3. Cross-validation choice for the regularization parameters (GCV). The resolution and performance of the methods are studied as a function of data type (continuous or discrete distributions of single exponentials), data sampling, and superimposed noise. All three methods are able to yield high-resolution estimates and are statistically valid. Qualitative comparison of the three methods in terms of maximum entropy is considered for "'worst case" limiting data. For discrete distributions comprising data of high signal-to-noise ratio (SNR), the order EM > CONTIN > GCV is observed for the entropy of the solutions. For continuous distributions of high SNR, the order EM > GCV > CONTIN is observed. The EM algorithm is suggested as the maximum likelihood (or maximum entropy) method when a high response to model error is not desired. The GCV algorithm yields a maximum likelihood estimate highly dependent on the model validity. The CONTIN algorithm provides a compromise between the two. - Anal. Chem. 65, 259-267 (1993). Dept. Chem. Biochem., Utah State Univ., Logan, UT 843220300 (USA) Statistical analysis of non-additivity in spectra of multicomponent mixtures. M.S. Khots, V.I. Nazarov and A.A. Lyovin. An algorithm is developed for the evaluation of non-additivity in the spectra of multicomponent mixtures. With this method it is possible to show areas where deviations from additivity are clearly seen. Using quantitative spectral analysis in these areas, interaction of the component must be taken into account. The method described can be used for the spectral analysis of mixtures, such as the products of petrochemical synthesis. - Chemom. Intell. Lab. Syst. 18, 281-284 (1993). All-

1 General analytical methods Russian Sci. Res. Inst. Oil Refining, Aviamotornaya 6, 111116 Moscow (Russia)

Non-linear robust regression procedure for calibration in flame atomic absorption spectrometry. P. Ko~cielniak. Robust regression methods based on the median, namely the single median and the repeated median methods, were extended to adapt some non-linear three-parametric models which covers problems occuring in FAAS. All essential features of the median methods were preserved owing to the modification suggested and the regression procedures are simple and easy to apply, allowing outliers to be detected and rejected. The resistance of the methods considered to the effect of outliers is discussed. The effectiveness of the median approaches and some advantages over the least-squares non-linear regression method are revealed in examples with both hypothetical data and real calibration data obtained from FAAS. - Anal. Chim. Acta 278, 177-187 (1993). Dept. Anal. Chem., Univ., 30060 Krakow (PL) Test of theory of overlap for two-dimensional separations by computer simulations of three-dimensional concentration profiles. Wenyan Shi and J.M. Davis. The potential applicability of a new statistical theory of overlap of two-dimensional separation are tested extensively by computer simulations. In these simulations, single-component spots were represented by three-dimensional concentration profiles with various amplitudes. Several characteristics of these profiles, including their number, saturation, symmetry, and amplitude distribution, were varied systematically. From these simulations, the resolution factors necessary to resolve these profiles into distinct maxima were determined and critiqued. Two procedures also were evaluated, by which the number of detectable single-component spots can be calculated from the coordinates of the observed maxima. - Anal. Chem. 65, 482-492 (1993). Dept. Chem. Biochem., South. Illinois Univ., Carbondale, IL 62901 (USA) Cross-peak classification in two-dimensional nuclear magnetic resonance spectra using a two-layer neural network. S.A. Corne, J. Fisher, A.P. Johnson and W.R. Newell. A two-layer simulated neural network has been trained to classify cross-peaks in two-dimensional nuclear magnetic resonance spectra. Examples of peaks for both network training and testing were selected. The trained network has been used to classify previously unseen dat. Spectral artefacts and authentic cross-peaks are distinguished. Peaks whose shapes have been modified, for example by overlap, are classified correctly. A spectrum for phoratoxin B, a protein of 46 amino acid residues, is used to illustrate the training and performance of the network. - Anal. Chim. Acta 278, 149-158 (1993). School Chem., Univ., Leeds LS2 9JT (GB) A two-way procedure for background correction of chromatographic/spectroscopic data by congruence analysis and least-squares fit of the zerocomponent regions: comparison with double-centering. Yi-Zeng Liang, O.M. Kvalheim, A. Rahmani and R.G. Brereton. A new method for background correction of two-way data that simultaneously corrects for base-line shift and for spectral background is described. First, the major principal components in the zero-component chromatographic regions are extracted before the appearance of the first eluting chemical constituent and after elution of the last chemical constituent in a peak cluster. Comparison of the loading patterns of the first principal component in the two zero-component regions by means of congruence analysis is used to reveal the presence of a constant spectral background and/or systematic baseline offset or drift. If baseline drift is revealed, the baseline for the whole chromatogram is estimated by means of a least-squares fit of the data from the two zero-component regions with retention time as 'independent' variable. A backgroundcorrected chromatogram is finally obtained by subtracting the estimasated spectral background and the estimated baseline from the original data. The new method is tested and compared with doublecentering using experimental multicomponent data. Chemom. Intell. Lab. Syst. 18, 265-279 (1993). Dept. Chem,, Univ., N-5007 Bergen Window evolving factor analysis for assessment of peak homogeneity in liquid chromatography. H.R. Keller, D.L. Massart and J.O. de Beer.

1.1.6

Data processing, chemometry, statistics

167

Fixed sized window evolving factor analysis and heuristic evolving latent projection methods can successfully be applied for assessment of peak homogeneity in liquid chromatography with photodiode array detection. The separation of prednisone and hydrocortisone, two pharmaceutical drugs having highly similar spectra, can be modulated from Rs = 0 to Rs = 1. To avoid problems caused by instrumental and experimtental difficulties, methods based on EFA require some form of data pretreatment. - Anal. Chem. 65, 471-475 (1993). Pharm. Inst., Vrije Univ. Brussel, B-1090 Brussels

of this method is fitting the absorption matrix obtained as a function of time and wavelength to a theoretical kinetic equation. This allows the resolution of mixtures of compounds with similar rate constants in a simultaneous fashion provided that they or their reaction products feature appreciable spectral differences from one another. The proposed method was applied to the resolution of Co(II) (0.1 - 1.0 gg ml- 1)-Ni(II) (0.5-5.0 gg m1-1) mixtures based on displacement from the EGTA complexes by 4-(2'-pyridylazo)resorcinol. - Anal. Chim. Acta 272, 339-344 (1993). Dept. Quim., Univ., E-07071 Palma de Mallorca

Improvement in the selectivity of the chemigram approach in gas chromatography/infrared spectroscopy. D. Pyo and Ken-ichi Harada. A new method is introduced which can deal with compounds with multiple characteristic patterns in multiple regions especially for GC/ IR. A computer method is presented to determine the proper ranges of frequencies within which characteristic patterns of absorbances for a given functional group can be found. The methods can be applied to Chemigram calculations for selecting aromatic compounds from collected GC/IR data. The computer acts as a functional-group selective detector. - Anal. Sci. 9, 279 - 2 8 3 (1993). Dept. Chem., Kangweon Nat. Univ., Chuncheon, South Korea 200-701

Reproducibility of results evaluated by the test for detecting recalcitrant catabolites (metabolites). W. Guhl and A. Ranke. The results for the analysis of two anionic and four nonionic surfactants are evaluated by the test for detecting recalcitrant catabolites (metabolites). The need to split up the dosing-phase into an adaptationand an evaluation-phase is discussed. The necessity to reach a plateauphase ( = evaluation phase) during the dosing-phase is shown. Disturbances of degradation caused by changes of abiotic factors prevent the evaluation of the test. Approaches are shown which allow the early recognition of those disturbances. The validity of the evaluated data is proved by consideration of the discussed problems: the same kind of investigations yield comparable results, even if data are found at different times or in different laboratories. - Tenside Surf. Det. 30, 6 - 1 4 (1993). Abt. ()kol., Henkel KGaA, W-4000 Diisseldorf (D)

I. Evaluation and correction of signal model errors in a matched filter for the quantification of chromatographic data. II. Quantification of chromatographic data using a matched filter: robustness towards noise model errors. B. van den Bogaert, H.F.M. Boelens and H.C. Smit. The robustness of the matched filter introduced by M.H.J. van Rijswick [Chromatographia 7, 491 (1974)] with respect to signal model errors as well as noise model errors is investigated. The errors are modelled as incorrect parameter values in an otherwise correct model, and their effect is monitored in the signal-to-noise ratio in the output of the matched filter. Normalization of the matched filter on the variance of the noise in the output makes the matched filter output a direct measure of this signal-to-noise ratio. The normalized matched filter output as a function of the signal model parameters is derived mathematically for a Gaussian signal and first order band-limited white noise. This function has a maximum for the correct signal model, suggesting the use of the maximum in the output of the normalized matched filter as the criterion in a Simplex optimization of the signal model as a means of correcting for signal model errors. Computer simulations confirm the feasibility of this approach. When the matched filter is made part of a procedure in which signal model errors are corrected by optimization of the filter performance, the noise model is critical at low signal-to-noise ratios and the correct model is to be preferred. - Anal. Chim. Acta 274, 71 - 9 7 (1993). Lab. Anal. Chem., Univ., 1018 WV Amsterdam (NL) Improved computer algorithm for characterizing skewed chromatographic band broadening. II. Results and comparisons. W.W. Yau, S.W. Rementer, J.M. Boyajian, J.J. DeStefano, J.F. Graft, K.B. Lira and J.J. Kirkland. The method of W.W. Yau and J.J. Kirkland [J. Chromatogr. 556, 111 (1991)] of extracting band-broadening parameters from noisy and skewed chromatographic peaks using an exponentially modified Gaussian peak shape model produces results that are more precise and less subject to baseline noise than previous methods for characterizing chromatographic band broadening. The method requires only precisely measurable experimental peak parametrs; peak retention time, peak height, peak area, and peak centroid (first moment). Accuracy and precision of the new method were compared with other digital approaches by using computer-synthesized peaks and experimental chromatographic data from many HPLC columns. The proposed method offers a reasonable compromise between accuracy, precision, and convenience. J. Chromatogr. 630, 6 9 - 7 7 (1993). E.I. DuPont de Nemours & Co., Cent. Res., Develop., Exp. Stat., Wilmington, DE 19880-0228 (USA) Computer method for the simultaneous kinetic determination of compounds in mixtures based on the use of diode-array spectrophotometry. A. Cladera, E. G6mez, J.M. Estela, V. Cerd~i and J.L. Cerdfi. Kinetic data provided by a diode-array spectrophotometer can be treated using the Newton-Gauss non-linear regression optimization model in the form of a computerized algorithm. The underlying principle

Interference theory: moment solution for two component adsorption chromatography. G.M. Zhong, F. Meunier and G. Guiochon. To study the interference in multicomponent non-equilibrium chromatography moment analysis is applied. By means of matrix operation the moment expressions have been extended to multicomponent systems. The expressions for the first and second moments of two component pertubations have been obtained for the first time. They are just the vectorization of those for the single component system, and they clearly show the interference between components. These results could be applied to establish an experimental procedure to measure adsorption equilibrium and kinetic data. - Chromatographia 36, 289-296 (1993). LIMSI-CNRS, F-91403 Orsay (F) A computer program for the optimal ion chromatographic determination of anions in waters. N. Gros and B~ Gorenc. An extensive data base was built up on the basis of statistically evaluated results of several ion chromatographic experiments to facilitate the planning of quantitative analysis o f F - , CI-, Br-, SO42 -, NO2 -, NO3 and HPO42- in natural waters. On the basis of these data a general form of computer program which can assist in method development has been developed. Necessary input data, sequence of main operations, necessary mathematical relationships and the output data are specified. The number of experimental steps can be reduced drastically. - Chromatographia 36, 251-258 (1993). Dept. Chem., Chem. Technol., Univ., 61000 Ljubljana (Slovenia) QSRR in liquid chromatography aided by computational chemistry. T. Hanai, H. Hatano, N. Nimura and T. Kinoshita. A quantitative structure-retention relation in reversed-phase liquid chromatography was studied with values calculated by computational chemistry. The physico-chemical values of the molecules were calculated by means of CAChe crM), a computer-program provided by SonyTektronik. These values were Van der Waals volume and surface area, calculated by MOPAC-BlogP, total energy calculated by Molecular Mechnics (MM2), kinetic, potential and total energies calculated by Molecular Dynamics (M D), and total energy and dipole moment calculated by Extended Huckel theory (EH). The precision of predicted retention time of non-ionic compounds is improved by using these values instead of Van der Waals volume calculated by Bondi's method and delocalization energy from literature. In general, retention in RP-LC may be related to the hydrophobicity of solutes. A combination of Van der Waals volume and kinetic energy of polyaromatic hydrocarbons is the most precise method to predict retention times in RP-LC. - J. Liquid Chromatogr. 16, 1453--1462 (1993). Int. Inst. Technol. Anal., Health Res. Found., Inst. Pasteur de Kyoto 5F, Kyoto 606 (J)

168

1 General analytical methods

Rapid method for drawing overlapping resolution maps (ORM) for thinlayer chromatography. E.J. Cavalli and C. Guinchard. The plotting of an overlapping resolution map is a very long process. Derivation of an original resolution formula provides an equation that gives directly the solvent-front migration-distance required for the separation of various compounds. This equation is used to speed up 30-fold the drawing of overlapping maps. This new drawing technique, called R ORM, gives results identical to those obtained by the classical ORM technique. It can be developed further to include a new variable in the overlapping maps. - Chromatographia 35, 372-374 (1993). Lab. Chim. Anal., UFR Med. Pharm., F-25030 Besan~on Cedex

is presented. Acoustic impulses are launched across a very thin (9 pm), tensioned polymer film consisting of adjacent control and measurement channels. Bound mass causes small changes (ns) in the transit time (gs), which is monitored sequentially on the two sensing areas. Because the polymer films are so thin, a 30-fold increase in sensitivity over quartz crystals can be achieved as was shown previously for a system using two separate resonant polymer film sensors. Changes in temperature and viscosity acting on both channels are well compensated, which should allow the determination of very small mass changes on the measurement area. - Analyst 118, 4 2 5 - 428 (1993). Phys. Dept., Univ. Coll. Galway, Nat. Univ. Ireland, Galway (IRL)

Estimation of the limit of detection and the limit of determination via calibration curve procedure. J. Hfidrich. In a first part the application of the new DFG-approach (1991) for an estimation of the limit of detection and the limit of determination via calibration curve procedure [DFG-Konzept ,,Ableitung der Nachweisgrenze und Bestimmungsgrenze nach dem Eichkurvenverfahren" 1991] for the residue analysis of 33 organochlorine and 11 heavy metal compounds is being described. The results of fortification experiments the values derived from regression analysis are being described in detail. In comparison with the results derivated from the mean blank values according to obligatory European Community's decision (NG3sD = MW + 3 DS, BG6sD = MW + 6 SD) the new DFG-approach leads to remarkably high values for both parameters. - Dtsch. Lebensmitt. Rdsch. 89, 35 - 4 2 (1993). Tierhyg. Inst. Freiburg, W-7800 Freiburg (D)

Potentiometric ion- and bioselective electrodes based on asymmetric polyurethane membranes. Dong Lin, M.E. Meyerhoff, H.D. Goldberg and R.B. Brown. A new type of asymmetric ion-selective membranes useful for fabrication of solid-state type biosensors is described which consist of a thin hydrophilic polymethane membrane possessing a high density of amine functional groups in the form of p01ylysine that is coated and fused to an underlying more hydrophobic plasticized polyurethane(PU)/terpoly(vinyl chloride/vinyl acetate/vinyl alcohol) (PVA)-based ion-selective membrane. The resulting asymmetric membranes function equivalently to normal PU/PVA membranes and conventional poly(vinyl chloride) type membranes in terms of potentiometric ion selectivity and dynamic response properties. The large amount of amine functional groups can be further activated for direct enzyme immobilization. Adenosine deaminase and urease are immobilized on ammonium- and protonselective membranes, respectively, to yield adenosine and urea electrodes with good dynamic responses and sensitivities. Advantageous use of this new membrane system for preparation of solid-state microfabricated enzyme-based sensors is also described. - Anal. Chim. Acta 274, 3 7 46 (1993). Dept. Chem., Univ., Ann Arbor, MI 48109 (USA)

Estimation of the limit of detection and the limit of determination via calibration curve procedure. Part 2: Application of the new DFG-approach in the residue analysis of anabolics and chemotherapeutics. Comparison with results of other statistical approaches. J. Hfidrich. A collaboratoy study was undertaken to test the new DFG-approach (1991) for an estimation of the limit of detection and the limit of determination via calibration curve procedure (DFG-Konzept ,,Ableitung von Nachweisgrenze und Bestimmungsgrenze nach dem Eichkurvenverfahren °', 1991). The laboratories found that the approach can be used in residue analysis of organochlorine pesticides as well as the heavy metals, anabolics and chemotherapeutics. The limits of detection (NGDFa) and limits of determination (BGoFG) found are 2.5 to 3 times higher than the results derived from the mean blank values standard deviations obtained according to obligatory European community's decisions. Reasons for this behaviour are discussed. The application of the DFG-approach varies from 2 to 10 h per compound, depending on the analytical method. The approach is suitable as an efficiency test of an analytical procedure, delivering information which cannot be obtained by just measuring the blank value. - Dtsch. Lebenm. Rdsch. 89, 35 - 4 2 (1993). Tierhyg. Inst., W-7800 Freiburg (D)

1.1.7

Sensors

Multi-layer conducting polymer gas sensor arrays for olfactory sensing. J.M. Slater, J. Paynter and E.J. Watt. A sensor based on polymer-coated array of conduction bands is described which allows differential conductivity measurements to probe the relative resistance of zones of a polymer. Conducting polymer poly(pyrrole) and its derivatives were used. The application of principal component analysis to the sensor responses allowed methanol, ethanol and propanol to be distinguished. The use of layered conducting polymers improved the discrimination of the sensor. A sensor consisting of four electrode pairs and two polymer layers is capable of separating the response of certain alcoholic beverages. - Analyst 118, 379 - 384 (1993). Anal. Sci., Birkbeck Coll., Univ. London, WCIH 0AJ (GB) Potential biosensor system employing acoustic impulses in thin polymer films. P.W. Walton, P.M. Gibney, M.P. Roe, M.J. Lang and W.J. Andrews. A new gravimetric sensor using acoustic pulse transmissions in thin polymer films with improved sensitivity in comparison to quartz crystals

Poly(pyrrole) based amperometric sensors: Theory and characterization. M.E.G. Lyons, C.H. Lyons, C. Fitzgerald and T. Bannon. An overview about problems concerning with the use of electropolymerized electronically conducting polymers as amperometric sensors is given with special regard to poly(pyrrole) based materials. Further, the characterization of the redox chemistry of these materials using cyclic voltammetry and complex impedance spectroscopy is presented. Finally, the mechanism and kinetics of mediation of outer sphere electron transfer processes at poly(pyrrole)based sensor materials is discussed. - Analyst 118, 3 6 1 - 369 (1993). Phys. Chem. Lab., Univ. Dublin, Trinity College, Dublin 2 (IRL) Modelling of coulometric sensor-actuator systems based on ISFETs with a porous actuator covering the gate. J. Luo, W. Olthuis, P. Bergveld, M. Bos and W.E. van der Linden. A brief review is given of the previously developed ISFET-based sensor-actuator system and the newly proposed system [L. Luo, W. Olthuis, B.H.v.d. Schoot, P. Bergveld, M. Bos and W.E.v.d. Linden in S. Middelhoek (ed.) Proc. Transducers' 91, The Sixth Conference on Solid State Sensors and Actuators, 1991, Elsevier, Amsterdam, p. 229] which employs a porous nobel metal as the actuator deposited at a short distance over the gate. The advantages and disadvantages of the different systems are compared. An analytical model is proposed for the new system with a porous nobel metal as the actuator. Two ways to make the porous gold actuator over the gate of the ISFET are described. The acid-base titration is chosen for the model study. The experimental results are in accordance with the theoretical description. - Anal. Chim. Acta 274, 7 - 23 (1993). Mesa Res. Inst., Fac. Electr. Engin., Univ., 7500 AE Enschede (NL) Electrode modification by long-chain, dialkyl disulfide reagent having terminal dinitrophenyl group and its application to impedimetric immunosensors. H. Taira, K. Nakano, M. Maeda and M. Takagi. A dialkyl disulfide compound carrying a terminal dinitrophenyl group (DNP) was synthesized. An organic monolayer therefrom was developed on the surface of a gold substrate and characterized by FT-IR and

1.1.7 Sensors electrochemical methods. Coupled with impedance measurements, a possible application of the modified electrode system to impedimetric immunosensors was demonstrated. The sensor gave electrical response to anti-DNP antibody at 10-103 ng cm a concentration. - Anal. Sci. 9, 199-206 (1993). Dept. Chem. Sci., TechnoI., Kyushu Univ., Hakozaki, Fukuoka 812 (J) Coated surface acoustic wave (SAW) sensor employing a reversible massamplifying ligand substitution reaction for real-time measurement of 1,3butadiene at low- and sub-ppm concentrations. Guo-Zheng Zhang and E.T. Zellers. SAW sensors coated with several Pt-olefin complexes are tested for the determination of low concentrations of butadiene gas. Especially coating with the square-planar Pt(lI)-olefin-~-complex PtC12-(1hexene)(pyridine)is investigated. Two 1-hexene molecules are substituted by each butadiene forming a bridged complex. Using a 30-MHz SAW oscillator, the rate of frequency change is linearly related to the butadiene air concentration from 150 ppb to > 13 ppm and a calculated detection limit of 101 ppb is obtained. Using a 60-MHz oscillator, the detection limit is reduced to 24 ppb. The potential for using this sensor to monitor occupational 1,3-butadiene exposures is discussed in light of the recently proposed occupational exposure limit of 2 ppm. - Anal. Chem. 65, 1340-1349 (1993). Dept. Environ., Industr. Health, School Public Health, Univ. Michigan, Ann Arbor, MI-48109-2029 (USA) Single drop method for determination of ions using an electrodeless piezoelectric quartz crystal. T. Nomura, Y. Ohno and Y. Takaji. To analyze a single drop an arrangement consisting of a horizontal platinum plate, a piezoelectric quartz crystal (quartz plate) on the platinum plate and a platinum wire set vertically above the centre of the platinum plate and at a distance of 0.8 mm from it in the same housing has beeen described. The platinum plate and the wire were connected to an oscillator. Procedure: Set the quartz plate on the platinum plate, set the recorder to record the frequency, place a single drop of reagent solution containing buffer and electrolyte on the quartz plate, leave for about 7 rain to obtain a constant frequency, place a single drop of the ion sample solution containing electrolyte and buffer on the quartz plate along with a platinum wire using a micropipette, read off the frequency shift (AF, Hz) between the frequency at the start (when the single drop of the sample solution was placed, F1) and that at 100 s later (F2), AF = F1 - F2, and calculate the concentration of the ion fiom a calibration graph constructed with a standard solution. Sulphate and potassium ions at levels of 50 ~ M - 0 . 5 mM can be determined using the barium salt or tetraphenylborate, respectively, with good reproducibility. Anal. Chim. Acta 272, 187 - 192 (1993). Dept. Chem., Fac. Sci., Shinshu Univ., Asahi, Matsumoto 390 (J) Glass pH electrodes with improved temperature characteristics. Part 2. Systems with conventional inner reference electrodes. D. Midgley. The use of internal filling solutions for glass electrodes is described which are based on zwitterionic buffers and show a linear variation of pH with temperature (at least 5-50°C). A judicious choice of buffer and inner reference element yields an electrode with almost the ideal characteristics of isopotential pH (= 7) and zero-point pH (= 7), which enable it to be with all pH meters. Other electrodes could readily be used with modern microprocessor-basedmeters. - Analyst 118, 4I - 4 5 (1993). Nat. Power plc, Technol., Environ. Cent., Leatherhead, Surrey, KT22 7SE (GB) Evaluation of three supports for an optical fiber ferric ion sensor. P. Pulido, J.M. Barrero, M.C. P6rez-Conde, C. Cfimara. The three supports : silica-gel, controlled pore glass (CPG) and sol-gel glass have been evaluated for use as the reactive phase of a fiber optic chemical sensor based on reflectance measurements. Chromazuroi S (CS) was immobilized on the tested supports by physical entrapment in sol-gel glass, covalent bonding to CPG and absorption on silica-gel. The latter provided the best analytical performance as evidenced by ease of immobilization, no losses of CS, and high speed of complex formation, and so it was chosen for developing a Fe(III) sensor. All variables affecting the response of the sensor, such as pH, buffer concentration, ionic strength, regeneration of active phase, response time, etc. were

169 evaluated. The proposed sensor is stable for more than 1000 iron determinations, provides a linear response from 10 to 500 ng/ml of Fe(III) and has a detection limit of 10 ng/ml. It is fairly selective and AI(III), F - , I and Br- are the main sources of interference. The sensor was successfully applied to determine iron in tap water and the method was more sensitive than FAA. - Quire. Anal. 12, 4 8 - 5 2 (1993). Dept. Anal. Chem., Fac. Chem., Complutense Univ. Madrid, E-28040 Madrid (E) Analytical utility of the iridium-based mercury ultramicroelectrode with square-wave anodic stripping voltammetry (SWASV). S.P. Kounaves and W. Deng. The combination of an It-based mercury ultramicroelectrode (UME) with SWASV provides a rapid, accurate and sensitive method for the determination of metal ions in aqueous solutions. Using Hg-UMEs of 5 - 1 0 ~m radii, samples were analyzed without any added electrolyte, deoxygenation, or forced convection. The peak stripping currents displayed a linear relationship with deposition times varying from I to 1200 s. Peak potentials and current remained substantially unchanged with electrolyte concentrations of 1 - l 0- 5 M. The reproducibility and useful lifetime of the Hg-UME was excellent over several days use. The application of SWASV theory for mercury film electrodes is shown to not entirely describe the response at the Hg-UME, especially at low squarewave frequencies. - Anal. Chem. 65, 375-379 (1993). Dept. Chem., Tufts Univ., Medford, MA 02155 (USA) Sodium-selective membrane electrode based on p-tert-butylcalix[4]arene methoxyethylester. K. Cunningham, G. Svehla, N.J. Harris and M.A. McKervey. Twelve calixarenes have been studied as prospective ionophores for sodium. Five of these have shown promising results in the liquid membrane form. All five have been successfully incorporated into poly(vinyl chloride) membranes, and applied as ion-selective electrodes for sodium. Electrode responses, selectivities towards alkali and alkaline earth metals as well as towards hydrogen and ammonium ions, temperature coefficients and response times have been studied. Based on these results, ptert-butylcalix[4]arene methoxyethylester has been chosen as the best ionophore for the preparation of sodium-selective electrodes. Limits of detection of 1 x 10 _4.3 tool Na/l can be obtained with this electrode. Details of electrode construction are presented. - Analyst 118, 341 345 (1993). Dept. Chem., Univ. College, Cork ([RL) Fibre optic oxygen sensor based on fluorescence quenching of evanescentwave excited ruthenium complexes in sol-gel derived porous coatings. B.D. MacCraith, C.M. McDonagh, G. O'Keeffe, E.T. Keyes, J.G. Vos, B. O'Kelly and J.F. McGilp. Optical sensors for oxygen based on coating a declad portion of an optical fibre with a microporous glass film prepared by the sol-gel process are proposed. A ruthenium complex [RuH-tris-(2,2'-bipyridine) or Ru ntris(4,7-diphenyl-l,10-phenanthroline)] is trapped in the nanometrescale cage-like structure of the porous film. In this sensor configuration the complex is excited by the evanescent field of the 488 nm radiation guided by the optical fibre. The luminescence from such complexes is quenched by oxygen and the sensors exhibit repeatable quenching behaviour when exposed to various concentrations of oxygen. The ratio R = Io/Iaoo where I0 and 1100 represent the detected signals from a sensor exposed to 100% nitrogen and 100% oxygen, respectively, is used as a measure of the sensitivity of the sensor. Sensors based on the diphenylphenanthroline complex exhibit greater sensitivity than those based on the bipyridine complex. - Analyst 118, 385-388 (t993). School Phys. Sci., City Univ., Dublin 9 (IRL) Mercury-free disposable lead sensors based on potentiometric stripping analysis at gold-coated screen-printed electrodes. J. Wang and B. Tian. The development of goId-coated screen-printed electrodes for decentralized testing of lead traces by potentiometric stripping analysis (PSA) is tested. The PSA operation obviates the need for oxygen removal, offers low background contributions, and minimizes surfactant interferences. Changes in the peak intensity and position (vs mercurycoated strips) offer new selectivity dimensions. Various experimental parameters are optimized to allow convenient monitoring of micrograms per liter lead concentrations following short deposition periods. Applica-

170

1 General analytical methods

bility to urine and drinking water samples is illustrated. The highly stable response of these screen-printed electrodes makes them very attractive for both single-use and multiple applications. - Anal. Chem. 65,1529 1532 (1993). Dept. Chem., Univ., Las Cruces, NM 88003 (USA)

mode. Cd, Ag, Mo, and Ni, in the nanogram to microgram per gram range were determined in five different SRMs with an average bias uncertainty and imprecision of less than 1%. - Anal. Chem. 65, 16021608 (1993). Nat. Inst. Standards, Technol., Gaithersburg, MD (USA)

Enzyme-based fiber optic zinc biosensor. R.B. Thompson and E.R. Jones. A fiber optic metal ion biosensor which is relatively sensitive and specific for zinc in the nanomole range is described which is based on the specific recognition of Zn 2+ by the enzyme carbonic anhydrase. The sensor transduces a change in the fluorescence of an inhibitor which binds to the zinc in the active site. The concentration of metal ion is proportional to the ratio of fluorescence intensity at two wavelengths, corresponding to the emission from bound and free inhibitor. Sensing of zinc may be performed through a single optical fiber. The sensor was mainly developed for the specific detection of Zn(II) in ocean water. Anal. Chem. 65, 730-734 (1993). Dept. Biol. Chem., Univ. Maryland School Med., Baltimore, MD-21201 (USA)

Near-IR spectroscopic determination of NaCI in aqueous solution. J. Lin and C.W. Brown. NaC1 concentrations in aqueous solutions have been determined by near-IR spectra between 1100 and 1900 nm. Models expressing the concentration of NaC1 are developed with linear and nonlinear regression with the use of the absorbances at selected wavelengths and with principal component regression (PCR) using entire spectra. Temperature perturbations on water bands interfere with the measurement of NaC1 but can be removed by linear or nonlinear regressions, or they can be accounted for by PCR. Standard errors of 5 mM and a detection limit of 15 mM are obtained for NaC1. - Appl. Spectrosc. 46, 1809-1815 (1992). Dept. Chem., Univ. Rhode Island, Kingston, RI 02881, (USA)

Preparation of fiber-optic trichloroethylene sensor for water with chemiluminescence detection after oxidation decomposition. K. Bansho, H. Tan, T. Imagawa and A. Miyazaki. For the determination of trichloroethylene (TCE) in groundwater, a fiber-optic sensor, based on chemiluminescence detection with luminol, was prepared and tested. The sensor consisted of a glass fiber bundle and a transducer. The transducer was composed of three components; a) a gas-permeable membrane to separate TCE from water, b) oxidizing agent which on reaction with TCE generates reaction gas needed for luminol chemiluminescence reaction, c) luminol solution. A mixture of sulfuric acid and sodium nitrate was selected as the oxidizing agent. The optimum pH of luminol solution was 8.5, and the optimum concentrations of luminol, H202, and sodium borate were 5 x 10 - 3 M, 2 x 10- 2 M, and 5 x 110 z M, respectively. The response time was shorter than 2 min. Calibration curve was linear at least from 0.05 to 0.6 gg/ml and the relative standard deviation (n=6) for 0.5 gg/ml was about 3%. Detection limit was 0.03 gg/ml, and a 10 m optical fiber sensor with photon-counting detection also showed the same sensitivity. - Bunseki Kagaku 42, 55 - 6 0 (1993). (Orig. Jap.). Nat. Inst. Resources Environm., 16-3, Onogawa, Tsukuba-shi, Ibaraki 305 (J)

1.2

Inorganic analysis

Simultaneous separation of ionic and noninnic compounds using reversedphase micellar chromatography. T. Okada. Micellar mobile phases are effective for the simultaneous separation of both organic nonionic compounds and inorganic ions. Nonionic compounds such as phenols are separated together with metal ions using mobile phases containing anionic micelles and a suitable ligand. Nonionic compounds are partitioned to the micelle and the stationary phase according to either the hydrophobicity or the lipophilicity, whereas inorganic ions electrostatically interact. The separation of phenols is therefore described using an usual partition model; that of inorganic ions obeys a model involving ion-exchange equilibria. - Anal. Sci. 9, 59--64 (1993). Fac. Lib. Arts, Shizuoka Univ., Shizuoka 422 (J) Selective application of chemical separation to isotope dilution inductively coupled plasma mass spectrometric analyses of standard reference materials. E.S. Beary and P.J. Paulsen. ICP-MS procedures in combination with isotope dilution are applied to the determination of Ni, Mo, Ag, and Cd in soils and Ni in leaves (SRMs). Isotope dilution analysis requires neither 100% recovery nor absolute isolation of the element(s) of interest, this results in considerable flexibility in the design of separations. Separated analytical samples were introduced into the ICP-MS, and high accuracy quantitative results were based on precise isotope ratio measurements made in the peak jump

Direct determination of aqueous carbon, phosphorus and sulfur using a kilowatt-plus helium microwave-induced plasma system with ultrasonic nebulization. Mingin Wu and J.W. Carnahan. The use of the modified 1600 W He-MIP in conjunction with an ultrasonic nebulizer is described for the determination of C, P and S in aqueous solutions. Emission was observed in the ultraviolet-visible spectral region. Unlike metals in aqueous solution, common forms of non-metals in aqueous solution exhibit significantly different vaporization characteristics in the nebulizer. The effects of molecular forms of aqueous carbon, phosphorus and sulfur upon sample introduction and resultant emission intensities were observed. Other studies include the examination of detection limits, linear responses and matrix effects. Detection limits in the range of 0.4-9.7 gg/ml and linear responses of more than 2 - 3 orders of magnitude were obtained. - J. Anal. At. Spectrom. 7, 1249-1252 (1992). Dept. Chem., Northern Illinois Univ., DeKlb, IL 60115 (USA) Electrothermal vaporization and ultrasonic nebulization for the determination of aqueous sulfur using a kilowatt-plus helium microwave-induced plasma. J. Alvarado, Mingin Wu and J.W. Carnahan. Inorganic and organic sulfur in aqueous solutions were determined using a helium microwave-induced plasma (kilowatt-plus) alternatively with sample introduction by means of ultrasonic nebulization (USN) and elctrothermal vaporization (ETV). Atomic emission lines in the near-infrared spectral region were chosen. Limits of detection ranged from 3 to 5 ppm using ETV and were a factor of 10 greater using USN. Linear responses were greater than two orders of magnitude. The matrix effects of sodium, potassium, lead, nickel and cadmium were investigated with ETV sample introduction and lead, nickel and cadmium were found to affect the sulfur signals only minimally. However, significant sulfur emission depression was caused by the easily ionizable elements, sodium and potassium. - J. Anal. At. Spectrom. 7, 1253-1256 (J992). Dept. Chem., Northern Illinois Univ., DeKalb, IL 60115 (USA) Aluminum determination using resonance ionization spectrometry. R. Zilliacus and J. Likonen. The determination of aluminum using resonance ionization spectroscopy has been investigated. The atomization of the sample was achieved by electrothermal heating in pyrolytically coated graphite in a vacuum. The atoms were excited in two resonant steps and ionized with an electric field pulse. The influence of the sample matrix on the aluminum signal and the use of matrix modifier were studied. Mg(NO3)2 were used as matrix modifier and preferable HNO3 for sample dissolution. The detection limit for aluminum determined in this work was 4 pg. Analytical results for some reference samples are presented. - Appl. Spectrosc. 46, 1828-1831 (1992). Techn. Res. Centre Finland, Reactor Lab., SF-02151 Espoo Thermal lens spectrophotometric determination of arsenic by hydride generation and reaction with silver(l) diethyldithiocarbamate. M.A. Rius Revert, G. Ramis Ramos, S. Cabredo Pinillos and J. Galb~n Bernal.

1.2

Inorganic analysis

The well known spectrophotometric method to detect As and AsH3 generated by NaBH4 with silver(I) diethyldithiocarbamate was adapted to thermal lens spectrophotometry; the TLS signal was measured using the 514.5 nm Ar + line for pumping. The TLS signal of the Ag(DDTC) solutions made the blank noise to be large and reduced the dynamic range. Sensitivity decreased when the Ag(DDTC) concentration was reduced below 10 -4 M, indicating that the reactions involved were not quantitative. Using 50 mW of pump power a limit of detection of 2 ng m1-1 arsenic was obtained. - Quire. Anal. 12, 7 - 1 1 (1993). Dept. Quire. Anal., Univ. Valencia, E-46100 Burjassot (E) Flow injection-electrothermal atomic absorption spectrometry for arsenic speciation using the Fleitmann reaction. M. Burguera and J.L. Burguera. Using a hydride generation system based on the Fleitmann reaction in combination with trapping the arsine in a graphite furnace for AAS inorganic As species can be determined. Efficient trapping of the arsine was achieved on Pd at 200°C, although other elements, such as Ru, Ce, Ag and Pt, can also be used to sequestrate the hydride, but with lower sensitivity. Optimization of the experimental parameters affecting the generation and trapping of the arsine and the arsenic atomization resulted in improved sensitivity, which allowed an absolute detection limit of 10 pg of As. The recommended method was satisfactorily applied to the determination of inorganic As species in various types of water samples and of total As in a variety of certified reference materials. J. Anal. At. Speetrom. 8, 229-233 (1993). Dept. Chem., Fac. Sci., Univ. Los Andes, M+rida 5101-A (YV) Accurate determination of selenium in the presence of iron by deuterium arc electrothermal atomic absorption spectrometry. S.J. Kumar and S. Gangadharan. To remove the spectral interference due to iron a pyrolytic graphite platform which is pretreated with a platinum-ascorbic acid mixture is used, which stabilizes and increases the selenium sensitivity. The method was tested on a solution containing 50 ng ml-1 of selenium in the presence of 2.5 mg ml 1 of iron. - J. Anal. At. Spectrom. 8, 127-129 (1993). Anal. Chem. Div., Bhabha Atomic Res. Centre, Bombay-400085 (1ND) Prompt ?-ray analysis of elements using cold and thermal reactor guided neutron beams. C. Yonezawa. The analytical sensitivities and detection limits of 71 elements are reported using elemental analysis by a reactor-neutron-induced prompt y-ray analysis (PGA) with cold and thermal beam guides. Boron, Gd, Sin, and Cd are the most sensitive elements with detection limits down to 1 to 7 ng. The decay y-rays of some elements such as F, A1, V, Eu, and Hf have a higher analytical sensitivity compared to their respective prompt y-rays. The analytical sensitivity of several heavy elements through detection of characteristic X-rays was higher than through the prompt y-ray detection. The present system is useful for the determination of, for example, ppb level of B in graphite and Be, ppb level of Gd, Sin, Eu, and Dy in high purity cerium(IV) oxide, and ppm to %level of H and Hf in Zr and zircaloy. This system is applicable to trace determination of Cd and Hg in environmental samples and also to major and minor elements determination in various kinds of samples that cannot be destroyed or dissolved. - Anal. Sci. 9, 185 - 193 (1993). Dept. Chem., Japan At. Energy Res. Inst., Tokaimura, Ibaraki 319-11 (J) Application of masking agents for elimination of interferences from metal ions in determination of mercury by cold vapour atomic absorption spectrometry. M.M. E1-Defrawy. The interfering effects of various foreign ions in the determination of mercury were studied by cold vapour atomic absorption spectrometry. There were serious depressing interferences from Ag, Au, Pt, Pd, Rh, Ru, Cu, Co, Ni and Pb. However, by using cyanide as a complexing agent these interferences could be completely eliminated over a wide range of interferent concentrations. Recovery of 102_+2.3% was obtained and the detection limit (S/N =2) was found to be 1.3 ng Hg. Analusis 21, 9 1 - 9 3 (1993). Chem. Dept., Fac. Sci., Univ., Mansoura, AR (ET)

171 Analysis of trace elements by glow discharge mass spectrometry using doped electrode technique. M. Saito. Glow discharge mass spectrometric determination of elements in steel using a solution doping method was studied. The instrument used was GDMS VG9000 and a high-purity graphite rod as the supporting electrode. The doped electrode samples were prepared by the synthesized standard solution containing 18 elements, or by dissolving the solid samples in acids. Yttrium was used as an internal standard. The impurities in steel sample were determined by using calibration curves obtained from the synthesized standard solutions, and the results were in good agreement with the certified values. The repeatability of this method was within 4% of relative standard deviation, and the detection limit for As was 0.5 ppm (3c~, n = 10). - Bunseki Kagaku 42, 2 1 - 2 5 (1993); (Orig. Jap.) Nat. Res. Inst. Metals, Meguro-ku, Tokyo 153 (J)

Effects of ion-pair ions on retention behaviors of metal complexes. XinXiang Zhang, Ming-Sheng Wang and Jie-Ke Cheng. The retention behaviors of Ce and Th complexes in presence of different types and concentration of ion-pair ions were studied. The ions studied were ammonium ion (NH4+), tetramethyl ammonium ion (TMA +), tetraethyl ammonium ion (TEA +), and tetrabutyl ammonium ion (TBA+). Only TBA + can by applied as ion-pair ion in the separation of Ce and Th .complexes on reversed-phase columns. - J. Liquid Chromatogr. 16, 1057-1068 (1993). Dept. Chem., Wuhan Univ., Wuhan 430072 (RC)

Ion-exchange selectivity and chromatographic separation of trivalent metals on titanium antimonate. H. Kaneko, M. Abe, T. Tsuji and Y. Tamaura. The determination of the ion exchange properties of micro amounts of A13 +, Ga 3+, In 3+, Cr 3+ and Fe 3 + on titanium antimonate containing different mole ratios of antimony and titanium, and the chromatographic separation of AI 3+, Ga 3+, and In 3+ was investigated. The titanium antimonate cation exchanger was prepared by coprecipitation of antimony to titanium at different mole ratios. The selectivity sequence A13+ < Cr a + < Ga 3+ < In 3+ < Fe 3+ was found for trivalent metal ions at an initial concentration of 10 -4 tool dm -a in nitric acid media. A high separation factor was observed for the Ga 3+ - A13+ pair on titanium antimonate with an antimony to titanium ratio of 0.34. - Chromatographia 35, 183-188 (1993). Dept. Chem., Tokyo Inst. Technol., Meguroku, Tokyo 152 (J)

Chromatography of some "s", "p", and "d" block metals on zirconium(IV) phosphoantimonate papers with aqueous and mixed solvent systems: separation of bismuth and mercury. A.K. Misra. Chromatographic studies of a large number of metal ions on zirconium(IV) phosphoantimonate (ZPA) papers were carried out using aqueous organic acids, dioxane/HCl mixtures and butanol/HNO3 mixtures as mobile phases. A number of interesting binary and ternary separations have been achieved. The method can be applied for example to the rapid quantitative separation of Bis + ( 5 - 20 ~g) and Hg 2 + ( 2 20 gg) from multicomponent mixtures such as industrial waste water. J. Planar Chromatogr. 1, 7 4 - 7 7 (1993). Dept. Chem., N.M.S.N. Dass (P.G.) College, Budaun 243601 (UP) (IND)

Separation of some metals as their anionic oxalate complexes by reversedphase ion-interaction chromatography. P. Janog. Mn 2+, Co z+, Ni 2+ and Cu 2+ can be separated as oxalate complexes on reversed-phase columns (Cls phase) with 2 retool/1 TBA-OH/2 retool/1 oxalic acid/l 0% methanol as mobile phase. The detection can be carried out at 254 nm. The analyte retention and separation can be influenced by the mobile phase pH and by the addition of an organic modifier to the mobile phase. The dependences of the analyte capacity factors on the mobile phase parameters have a similar character, which were observed in common anion separation by ion-interaction chromatography. - J. Chromatogr. 635, 257-263 (/993). Res. Inst. Inorg. Chem., 40060 Usti nad Labem (Czech Republic)

172 Separation and quantification of some metal ions by RP-HPLC using EDTA as complexing agent in mobile phase. M.L. Marina, P. AndrOs and J.C. Diez-Masa. Ni(II), Co(II), Cu(II), Mn(II), Fe(III), Pb(II), Cr(III), and Hg(II) as complexes of EDTA can be separated by ion-pair RP-HPLC. The separation of metal ions from inorganic anions such as Cr207 z- and NO3- is possible by employing a positively charged counterion in the mobile phase. The influence of the nature and concentration of counterion, organic modifier content, ionic strength, EDTA concentration and pH of the mobile phase on the retention and selectivity has been investigated. Optimum conditions for multi-element separations can be achieved with methanol/water (90:10), 0.01 M EDTA, 0.02 M TBA, pH 3.25. Quantitation of metal ions was achieved with spectrophotometric detection. Detection limits ranged from 300 pg for Fe(III) to 35 ng for Cr(III) with a linearity of 2 - 3 orders of magnitude. Some applications of the technique to the separation of multielement mixtures are shown. Chromatographia 35, 621-626 (1993). Dept. Quim. Anal., Fac. Cie., Univ., 28871 Alcalfi de Henares (Madrid) (E) Normal phase, reversed phase and chelation thin layer chromatographic studies of some toxic metal ions in two component solvent systems containing DMSO: Quantitative separation of Pb 2÷ from Hgz 2+, Hg 2+, TI +, Bi 3+, SH4+, and Sb 3+. S.D. Sharma, S. Misra and R. Gupta. A systematical study was carried out for normal phase, reversed phase and chelation thin layer chromatography of some toxic metal ions in DMSO-HNO3 and DMSO-HCI systems. TBP and TBA impregnated layers were used for reversed phase thin layer chromatography. Quantitative separation of lead from binary mixtures and synthetic alloys, containing Cu 2+, Sn 4+, Bi 3+, Sb 3+, Cd 2+, Ni 2+, Hg22+ and Hg 2+ has been experimentally achieved, as well as of elements with different oxidation states. - J. Liquid Chromatogr. 16, 1833 1843 (1993). Anal. Res. Lab., Dept. Chem., Hindu Coll., B-3, Jigar Vihar, Moradabad-244 001 (IND) Metal ion capillary zone electrophoresis with direct UV detection: determination of transition metals using an 8-hydroxyquinoline-5-sulphonic acid (HQS) chelating system. A.R. Timerbaev, W. Buchberger, O.P. Semenova and G.K. Bonn. HQS is used as reagent for the separation and determination of transition metal ions after the precolumn formation of negatively charged chelates. Multi-component mixtures of transition metal complexes with HQS were separated in about 10 rain in a fused-silica capillary column with a borate buffer of pH 9.2 at an applied voltage of 15 kV followed by direct UV detection. The capillary pretreatment with an electroosmotic flow modifier, namely a tetraalkylammonium salt, is necessary to achieve resonable migration times of these metal complexes. Incorporating the chelating reagent in the electrophoretic buffer markedly improves the detectability of relatively unstable chelates, such as those of Co(II), Zn(II) and Cd(II), and allows the separation of metal ions that form unstable HQS chelates, such as Mn(II) and alkaline earth metals. The effects of electrophoretic buffer parameters affecting the complexation reaction and migration behaviour are discussed. Linearity of calibration graphs is observed for about three orders of magnitude with sub-ppm detection limits. The applicability of the method to the analysis of real samples is demonstrated. - J. Chromatogr. 630, 3 7 9 389 (1993). Dept. Anal. Chem., Univ., A-4040 Linz Metal ion capillary zone electrophoresis (CZE) with direct UV detection: Separation of metal cyanide complexes. W. Buchberger, O.P. Semenova and A.R. Timerbaev. CZE can be effectively applied for the separation of cyanide complexes of Fe(III), Cu(I), Fe(II), Ni(II), Cr(III), Hg(II), Pd(II), Ag(I), Cd(II), Zn(II), Co(II) and Cd(III). The separation was carried out on a fused silica capillary with 20 mM phosphate buffers containing 1--2 mM sodium cyanide. The complexes were detected by direct UV absorption at 214 nm; detection limits are in the mid ppb range for all metals except cadmium and zinc. Precious metals and metal ions with slow complexation rates as Cr(III) and Co(III) can be determined, oxidation states can be differentiated. - J. High Resol. Chromatogr. 16, 153156 (1993). Dept. Anal. Chem., Inst. Chem., Univ., A-4040 Linz

1 General analytical methods Effect of metal nitrates as matrix modifiers for the determination of tellurium by graphite furnace AAS. K. Matsusaki, T. Yamamoto and T. Oishi. A mixture of nickel nitrate, aluminium nitrate and EDTA ammonium salt is used as matrix modifier for the determination of tellurium by a graphite furnace AAS. Nickel nitrate acted as a thermal stabilizer for the analyte in the furnace before atomization. When the mixture of nickel nitrate (0.02 M), aluminium nitrate (0.01 M) and EDTA tetraammonium salt (0.02 M) were added, the chloride interference was removed. The sulfate interference also could be removed by this matrix modifier. The tolerance concentration of coexisting sulfates were about 100 or more times larger than that resulted in the absence of modifier. The addition of this matrix modifier was applied to the direct determination of trace tellurium in copper alloy. - Bunseki Kagaku 42, 1 - 6 (1993); (Orig. Jap.) Dept. Appl. Chem., Chem. Engin., Fac. Engin., Univ., Yamaguchi 755 (J) Separation of 90y from 9°St by solvent extraction with ionizable crown ethers. D.J. Wood, S. Elshani, H.S. Du, N.R. Natale, and C.M. Wai. The complexation of y3+ and Sr 2+ by ionizable crown ethers is investigated according to the molecular structure of the complexing ligand, sym-Dibenzo-16-crown-5-oxyacetic acid and its analogues are selective for the extraction of y3 + over Sr 2 + from aqueous solutions into chloroform. The size of the macrocyclic cavity, the tether length of the lariat, the attachment of alkyl functional groups to the lariat, and the identity of the ionizable group can affect selectivity and extraction efficiency. When the carboxylic acid at the terminal end of the lariat is replaced by a hydroxamic acid, the selectivity for y3÷ over Sr 2÷ is significantly increased. Using these ionizable crown ethers as extractants, 90y fractions of greater than 99.9% purity can be obtained in a single solvent extraction step from solutions of9°Sr. - Anal. Chem. 65, 1350 1354 (1993). Dept. Chem., Univ. Idaho, Moscow, ID 83843 (USA) The separation and indirect visible detection of rare earth metal cations on a dye-coated stationary phase. T.A. Walker. A Phenol Red coated stationary phase was successfully used for the separation of rare earth metal cations. The mobile phase variables that were found to affect metal cation retention and resolution are: concentration of dye, concentration of organic modifier, mobile phase pH, type and concentration of ligand, and ionic strength. A polymer-based stationary phase was used in this study and detection of the metal cations was accomplished by indirect visible detection at 490 nm. - J. Liquid Chromatogr. 16, 1573-1587 (1993). Pharm. Anal. Sci., Marion Merrell Dow Inc., P.O. Box 9627, Kansas City, MO 64•34 (USA) Spectrophotometric determination of niobium with hydrogen peroxide and 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol in steel and apatite after its extractive separation as ~-benzoin oxamate. M. Jarosz and S. Oszwatdowski. A simple and sensitive spectrophotometric method for the determination of gg Nb based on its complex with 2-(5-bromo-2-pyrdylazo)-5diethylaminophenol in the presence of hydrogen peroxide is developed. The molar absorptivity at 591 nm is 7.43 × 104 1 mol 1 cm 1 at pH 4.0 _+1.0. This method becomes selective for niobium(V) after a preliminary extraction of its complex with s-benzoin oxime from 5 - 9 M hydrochloric acid. It has been applied to the determination of niobium in materials of certified Nb content, steel and apatite samples. - Anal. Sci. 9, 285--288 (1993). Dept. Anal. Chem., Techn. Univ., 00-664 Warsaw (PL) Stopped-flow kinetic determination of a binary mixture: Simultaneous determination of europium and cerium. J. Wang, W. Ruan and R. He. A kinetic method is proposed for the simultaneous determination of europium(II) and cerium(III), based on their inductive action on the Cr(VI)-iodide redox reaction in weak acidic medium. The reaction rate was followed by the stopped-flow spectrophotometric technique using starch-iodine complex as indicator. The method can be used for the determination of europium and cerium after reduction with zinc metal powder in the concentration ranges 0 2.1 and 0 - 1 . 8 pg/ml, respec-

1.2

Inorganic analysis

tively. The detection limits are 0.015 gg/ml Eu and 0.010 gg/ml Ce. 100 to 1000 times higher concentrations of other rare earth metal ions and Th 4+, A13+, Mn 2+, Hg 2+, Co 2+, Ni z+, Cu 2+, Pb 2+ do not interfere. The method is applied to the determination of europium and cerium in a synthetic sample and in barium yttrium fluoride fluorescent material, with relative standard deviation of about 4%. - Mikrochim Acta 110, 241--247 (1993). Chem. Dept., Yantai Normal Co11., 264000 Yantai (RC)

Simultaneous determination of neodymium and erbium in rare earth mixture with 5,7-dibromo-8-hydroxyquinoline and TX-100 by third-derivative spectrophotometry. Nai-Xing Wang, Qing-Chang Wu, Jun-Bo Shi and Ping Qi. The absorption spectra of 4f electron transitions of the complexes of Nd and Er with 5,7-dibromo-8-hydroxyquinoline in the presence of octylphenol poly(ethyleneglycol)ether by normal and third-derivative spectrophotometry can be used for their determination in mixed rare earths. The proposed method is free of interference of other rare earths. The calibration graphs were linear up to 18 gg/ml of Nd and 21 gg/mI of Er (in the final solution). The derivative molar absorptivities are 395 I tool- 1 cm- ~ for Nd and 342 1 mol - 1 cm 1 for Er. The corresponding values of Sandell's sensitivity were 0.36 and 0.49 gg cm 2, respectively. The relative standard deviations evaluated from ten independent determinations of 2.5 gg/ml of Nd and Er are 1.5 and 3.8% for Nd and 1.8 and 4.1% for Er in absence and presence of 70 gg of La, respectively. The detection limits (signal to noise ratio = 2) are 0.23 gg/ml for Nd and 0.30 gg/ml for Er. - Mikrochim Acta 110, 119-126 (1993). Dept. Chem., Shandong Univ., Jinan, 250100 (RC) Semi-Xylenoi Orange complex of zirconium(IV) as a photometric reagent system for fluoride based on mixed ligand complex formation. A. Yuchi, N. Hokari, H. Wada and G. Nakagawa. Zr(IV) and Semi-Xylenol Orange (SXO) (1:1) reacts rapidly with fluoride ion at pH 2 to cause an increase in absorbance at about 530 nm. The calibration graph was linear up to I x 10 -s mol dm 3 In a flow injection system, a detection limit (S/N = 3) of 2.5 x 10 - v tool dm - 3 was obtained with a sample throughput of 60 h - 1. _ Analyst 118, 219 222 (1993). Dept. Appl. Chem., Nagoya Inst. Technol., Showa, Nagoya 466 (J) Detection of vanadium by laser-excited atomic fluorescence spectrometry (LEAFS) in a side-heated graphite furnace. S. Sj6str6m, O. Axner and M. Norberg. Vanadium can be determined in deionized water at the picogram level by double resonance ETA-LEAFS using side-heated graphite tube cuvettes. The limiting factor for the detection of vanadium was contamination from the graphite furnaces. J. Anal. At. Spectrom. 8, 375 - 378 (1993). Dept. Phys., Chalmers Univ. Technol., Univ., S-41296 G6teborg Decolorization reactions between chromium(VI) and three colour reagents. Determination of chromium(VI) by flow injection analysis. Chen Xingguo, Xu Yanjun and Hu Zhide. Simple, rapid and selective methods are reported for the determination of Cr(VI) based on the decolorization of 1,8-dihydroxy-2-(4'-chloro-2'phosphonophenylazo)-7- (6",8"-disulfonaphthylazo)-3,6-disulfonaphthalene (RI); 1,8-dihydroxy-2-(4'-chloro-2'-phosphonophenylazo)-7(4"-sulfonamidephenylazo)-3,6-disulfonaphthalene(RII); and 1,8-dihydroxy-2-(4'-chloro-2'-phosphonophenylazo)-7-(p-hippuric acid azo)3,6-disulfonaphthalene (RIII). Loss of absorbance of three colour reagents at maximum absorption wavelengths is proportional to the concentration of chromium(VI) in solution. The method has been applied to the determination of Cr(VI) in steel with rel. errors < 5%, a linear response from 0.84 to 6.72 pg/ml and optimum acidity of 1.3-1.7 M HzSO~. -- Anal. Letters 26, 605-612 (1993). Dept. Chem., Univ., Lanzhou, 730000 (RC) Measurement of ultratrace levels of chromium by adsorptive-catalytic stripping voltammetry in the presence of cupferron. J. Wang, Jianmin Lu and K. Olsen. Coupling of adsorptive accumulation with the catalytic action of cupferron can be used for the ultrasensitive adsorptive-catalytic stripping

]73 (voltammetric and potentiometric) of trace levels of chromium. The method offers higher sensitivity than previous adsorptive stripping schemes for chromium. Optimum experimental conditions were found to be a 1 x 10-3 mol 1-1 piperazine-N,N'-bis(ethanesulfonic acid) solution (pH 7.0) containing 1 x 10 -~ tool 1-1 cupferron and a preconcentration potential of 0.82 V. A preconcentration time of 1 rain results in a detection limit of 1.0 ng 1-1. The relative standard deviation at 100 ng 1-1 is 2.4% (n=20, for 20 s preconcentration). Convenient measurements of chromium in the presence of dissolved oxygen are possible. The identical stripping response for chromium(III) and chromium(VI) solutions makes the method applicable to the measurement of the total chromium content. The simultaneous determination of chromium and uranium is illustrated. The method is applied to the analysis of soil and groundwater samples. - Analyst 117, 1913-t917 (1993). Dept. Chem., Univ., Las Cruces, NM 88003 (USA)

The catalytic adsorptive stripping voltammetric determination of chromium with TTHA and nitrate. M. Paneli, A.V. Voulgaropoulos and K. Kalcher. A sensitive voltammetric method is presented for the determination of trace amounts of total chromium (Cr(III) and Cr(VI)) in natural waters, employing the square wave mode. The method is based on the preconcentration of the Cr(III)-TTHA complex by adsorption at the HMDE at the potential of - 1.0 V vs. Ag/AgC1. The adsorbed complex is then reduced producing a response with a peak potential of - 1.29 V and the peak height of the Cr(III) reduction is measured. The catalytic action of the nitrate ions on the Cr(III)-TTHA reduction has been elucidated using cyclic voltammetry. The adsorption of chromium complexes at the HMDE was investigated using out-of-phase a.c. voltammetry and the potential range of adsorption was determined. Optimal conditions for the determination of the total chromium concentration in the range 155 - 2000 ng 1-1 have been established. The determination limits is 15 ng 1-1 and the RSD is 3.5% for chromium concentrations _> 200 ng 1-1. The usefulness of this method is demonstrated by determinations of the total chromium content in lake, sea and rain water. Mikrochim. Acta 110, 205-215 (1993). Lab. Anal. Chem., Dept. Chem., Aristotelian Univ. Thessaloniki, GR-54006 Thessaloniki Experimental and theoretical studies of the factors that influence the determination of molybdenum by electrothermal atomic absorption spectroscopy. Z. Benzo, P. Araujo, A. Sierraalta and F. Ruette. The effect of HC1 and HNO3 on the sensitivity of the Mo-signal of EAAS was investigated by the response surface method and by modeling Mo-graphite interactions using quantum mechanical calculations. A multivariate optimization approach was carried out using the Doehlert matrix and a cubic equation to approximate the experimental response. HCI and HNO3 produce an enhancement of the Mo signal with respect to the nonacidified solution. This enhancement is interpreted as a decrease of memory effects caused by the acid presence which facilitates formation of Mo species that can be more easily atomized. Qualitative theoretical calculations (CNDO) reveal that the adsorption of Mo and MoO3 occurs on 6-fold center sites. Protons coadsorbed on the graphite surface facilitate the migration of Mo species. - Anal. Chem. 65, 1107 1i13 (1993). Lab. Quim. Anal., Lab. Quim. Comput., Centro de Quim., IVIC, Apart. Postal 21827, Caracas 1020-A (YV) On-line electrochemical preconcentration of manganese for graphite furnace atomic absorption spectrometry using a flow-through electrochemical cell. E. Beinrohr, M. Rapta, Maw-Lin Lee, P. Tsch6pel and G. T61g. A flow system incorporating a 2-electrode electrochemical microcell with a working electrode made from crushed reticulated vitreous carbon and a graphite furnace AAS instrument was used for the preconcentration and determination of trace amounts of Mn. The sample, rinsing and elution solutions were pneumatically transported through the system. Mn 2÷ ions can be quantitatively deposited both anodically and cathodically at a voltage of + 1.5 to + 3 V and - 2.5 to - 4 V, respectively applied to the cell. Samples of 0.1 to 1 ml volume were analyzed within 5 - 1 0 min. The limits of detection and determination were 8.7 and 29 pg, respectively. The reproducibility was 1.5 to 5%. The electrochemical behaviour of Mn in the flow system was studied by using a 3-electrode flow-through cell coupled on-line to a flame AAS instrument. -

1 General analytical methods

174 Mikrochim. Acta 110, 1 - 1 2 (1993). Max-Planck-Inst. Metallforschung, Lab. Reinstoffanalytik, W-4600 Dortmund 1 (D)

Flow-injection extraction-spectrophotometric determination of manganese(VII) with benzyltributylammonium cations. D.T. Burns, S.A. Barakat, M. Harriott and M.S. E1-Shahawi. The development of a flow-injection manifold using benzyltributylammonium chloride as an ion-pairing extractant for permanganate and the application of the system to the spectrophotometricdetermination at 548 nm of Mn in steels after oxidation of Mn(II) to Mn(VII) by KIO4 is described. The carrier stream was a pH 6 buffer containing 10% (w/v) ammonium fluoride and the reagent stream was 0.10% (w/ v) benzyltributylammonium chloride. The injection rate was 20 h - 1. The calibration graph is linear up to 25 gg ml- 1 and the detection limit (3 x baseline noise) is 0.91 gg m1-1 Mn(VII), based on 250-/xl injection volumes. - Anal. Chim. Acta 270, 213 - 215 (J 992). Dept. Anal. Chem., Univ., Belfast BT9 5AG (GB) Preconcentration and determination of a trace amount of manganese as its thenoyltrifluoroacetone complex with dibenzo-18-crown-6 by means of synergistic extraction and atomic absorption spectrometry. M. Billah, T. Honjo and K. Terada. Mn can be extracted completely and rapidly with thenoyltrifluoroacetone (TTA) and dibenzo-18-crown-6 (DB18C6) at the ppb to sub ppb level from natural waters by synergistic extraction with subsequent AAS. The effect of various factors (pH, shaking time, preconcentration factor and foreign ions etc.) on the extraction and back extraction of manganese has been investigated. The manganese TTA chelate in o-dichlorobenzene forms stable adducts with DBISC6 [Mn(TTA)2.nDBI8C6, n = 1 - 2 ] ; the stability constants ([3n) of the adducts were determined by a curvefitting method as log 131 = 4.43 and log 132 = 6.85. - Anal. Sci. 9, 251 254 (1993). Dept. Chem., Fac. Sci., Kanazawa Univ., Kanazawa 920-11

(J) Studies on the application of photochemical reactions in a flow injection system. Part 2. Simultaneous determination of iron(II) and iron(III) based on the photoreduction of the iron(III)-phenanthroline complex. Ren-Min Liu, Dao-Jie Liu and Ai-Ling Sun. A flow through photochemical reactor was constructed for the simultaneous determination ofiron(II) and iron(III) based on the photoreduction of the iron(III)- 1,10-phenanthroline complex. Optimum analytical conditions were established. A 100 mm 3 sample injection gave linear working ranges of 0.1 - 120 ppm of iron(II) and 0.2-120 ppm of total iron. The sample throughput was 4 0 - 6 0 h-1. The proposed method was applied to the determination of iron(II) and iron(III) in synthetic mixtures of standard iron(II) and iron(III) and the catalyst for synthetic ammonia manufacture. - Analyst 117, 1767-1770 (1992). Dept. Chem., Teachers Coll., Liaocheng, Shandong (RC) Application of the generalized standard addition method in the twocomponent potentiometric titration of Fe(II) and Fe(IIl). A comparison with other calibration methods. J. Kochana and A. Parczewski. The generalized standard addition method, conventional onecomponent standard addition method, and two-component calibration were applied in the simultaneous potentiometric complexometric titration of Fe(II) and Fe(III) in 0.5% NaC1 matrix. The best results have been obtained with the use of two-component calibration. The onecomponent standard addition method has given better results for Fe(II) than for Fe(III). As compared with the conventional standard addition method the GSAM has appeared to be more reliable for both analytes. The reasons for the above results have been discussed and explained. [See also Chem. Analit. 37, 6 6 7 - 672 (1992)] - Chem. Analit. 37, 673 -681 (1992). Dept. Anal. Chem., Jagiellonian Univ., 30-060 Krak6w (PL) Spectrophotometric determination of nickel after separation by adsorption of its piperidinedithiocarbamate on microcrystalline naphthalene. A. Kumar and M, Jaln. Nickel forms a water insoluble, thermally stable 1:2 complex with piperidinedithiocarbamate which is easily adsorbed into microcrystalline

naphthalene in the pH range 3 . 0 - 8.5. Beer's law is obeyed over concentration range from 10 to 100 gg of nickel in 10 ml of dimethylformamide at 390 nm. The molar absorptivity and sensitivity are found to be 5.7 x 103 1tool-1 cm- 1 and 0.0102 gg cm -2, respectively. Samples containing 36.0 lag of nickel give a mean absorbance of 0.350 with a relative standard deviation of 0.77%. The method is selective and has been applied for the determination of nickel in certain alloys. - Chem. Analit. 37, 7 3 - 7 8 (1992). Dept. Chem., D.A. Univ., Indore-452001 (IND)

Simultaneous determination of nickel(II) and cobalt(II) by square-wave adsorptive stripping voltammetry on a rotating disc mercury film electrode. A. Economou and P.R. Fielden. The suitability of adsorptive stripping voltammetry for the simultaneous determination of Ni It and Co II was demonstrated. The metal ions were complexed with dimethylgtyoxime and adsorbed on the surface of a glassy carbon rotating disc electrode, which was pre-plated with mercury. The stripping step was carried out by using a square-wave potential-time excitation signal. An electrochemical cleaning of the mercury film was employed, enabling the same mercury film to be used for a series of measurements. The limits of detection were 12 ng 1- ~ for Co II and 14 ng 1-1 for Ni n (for /20 s preconcentration), the relative standard deviation was typically about 2 - 3% (at the 1.2 lag 1-1 level) and linearity held for a concentration range of at least two orders of magnitude. Analyst 118, 47 - 51 (1993). Dept. Instr., Anal. Sci., UMIST, Manchester g 6 0 1QD (GB) Spectrophotometric determination of cobalt in high-salt concentration solutions by flow injection method. Y. Hayashibe, M. Takeya and Y. Sayama. Co can be determined in electrolytes (as used for wet refining) by an FIA-method with nitroso-R salt at 480 nm. The sample solution containing about 150 g Zn 1-1 was injected four times into a carrier stream, and the carrier stream was merged with 2 M acetate-0.5 M citrate buffer solution (pH 6) to form a sample solution stream. The colorimetric reagent (1.0% w/v)) was injected into the sample solution stream. Then coexisting metal complexes were decomposed by mixing with 2 M sulfuric acid-1% (v/v) hydrogen peroxide solution. The proposed system was operated automatically by a personal computer and allowed 6 samples to analyze per hour. Precision of the system was a RSD of 8% at the 0.5 gg Co ml 1 level and detection limit was 0.05 gg Co ml- 1. _ Bunseki Kagaku 41,633 - 6 3 8 (1992); (Orig. Jap.) Mitsubishi Materials Co., Cent. Res. Inst., 1-297 Kitabukuro-cho, Oomiya-shi, Saitama 330

(J) Spectrophotometric determination of cobalt(III) with 1-(2-pyridylazo)-2naphthol and cetyltrimethylammonium bromide. J. Kobytecka. The cationic surfactant cetyltrimethylammonium bromide (CTA) solubilizes Co(III)-PAN complex which is insoluble in water. In the presence of CTA the molar ratio of cobalt to PAN is 1:2. The optimum conditions for determination of cobalt were found. Beer's law is obeyed over the range 0.1 - 1.0 gg ml- 1 of cobalt, e = 2.17 x 1041 tool- 1 cm- 1 at 570 rim. The main advantages of this method are as follows: relatively high sensitiviy, simple and time-saving procedure, good accuracy and precision and wide pH range for complex formation. The method was used to determine cobalt in vitamin B12. - Chem. Analit. 37, 3 6 9 - 376 (1992). Inst. Gen., Ecol. Chem., Techn. Univ., 90-924 Lode, (PL) Spectrophotometric determination of cobalt(liD with 2-diethylamino-5nitroso-l,4,5,6-tetrahydropyrimidine-4,6-dione (ENPD). M. Tsuchiya and Y. Iwanami. To determine Co(III) its complex with ENPD can be used. This yellow complex, which is water soluble, is stable even at pH 1.0, while other metal complexes decompose at this pH. The cobalt(III)-ENPD complex has a molar absorptivity of 6.3 x 104 1 mo1-1 cm -1 at 385 nm. The formation of the complex is quantitative over the pH range from 4.8 to 6.8. The molar ratio of cobalt(III) to ENPD in the complex is 1:3 according to the continuous variation method. The proposed method was satisfactorily applied to the determination of cobalt in various samples, such as monel, nimonic and magnet alloys. - Anal. Sci. 8, 869-872 (1992). Dept. Chem., Keio Univ., Hiyoshi, Yokohama 223 (J)

1.2

Inorganic analysis

Flow-through photometric sensor for the determination of cadmium at the nanogram per miililitre level. P. Richter, M.D. Luque de Castro and M. Valcfircei. A sensor for the determination of cadmium is described which is based on the transient retention of the analyte as CdI4 a- in a flow-cell containing QAE-Sephadex anion exchange resin after homogeneous reaction of the analyte with iodide. Subsequently a heterogeneous complex displacement reaction with 4-(2-pyridylazo)-resorcinol takes place. The formation of the colored chelate and detection occurs simultaneously. The method features a determination range between 30 and 500 ng/ml of Cd(II) with relative standard deviations of 1.8 % and 3.4% for 200 and 50 ng/ml of Cd(II), respectively. The selectivity involved in the use of the proposed sensor is shown in the study of interference. Anal. Letters 26, 733-744 (1993). Dept. Anal. Chem., Fac. Sci., Univ. Cdrdoba, E-14004 C6rdoba (E) Subnanogram determination of inorganic and organic mercury by heliummicrowave induced plasma-atomic emission spectrometry. K. Fukushi, S.N. Willie and R.E. Sturgeon. A simple method is proposed for the determination of inorganic and organic mercury by helium-microwave induced plasma-AES following cold vapor generation. Whereas only inorganic mercury was reduced by stannous ion in an acidic medium, total mercury were reduced by stannous ion in the presence of cupric ion in a basic medium. Organic mercury can be determined as the difference between total and inorganic mercury. Detection limits for inorganic and organic mercury were 11 and 10 pg, respectively. The accuracy of the proposed method was verified through the determination of inorganic, total and organic mercury in two marine biological standard reference materials. - Anal. Letters 26, 325-340 (1993). Res. Inst. Marine Cargo Transport, Univ. Mercantile Marine, Higashinada-ku, Kobe 658 (J) Determination of mercury by flow injection-atomic fluorescence spectrometry using chromium(II) reduction-cold vapor generation. H. Tanaka, M. Kouno, H. Morita, K. Okamoto and S. Shimomura. Cr(II) produced by reduction of Cr(III) was used as reductant under acidic conditions prior to AFS determination of Hg. The atomic fluorescence intensity of the vaporized mercury was determined at 253.7 nm on an atomic fluorescence spectrometer coupled with a flow injection device. The chromium(II) reduction system could completely reduce the mercury-iodide complex, HgI41-, to elemental mercury, thus enabling an atomic fluorescence determination. The addition of iodide ions (> 10 mg 1 1 as the final concentration) stabilized mercury ions as HgI42 and showed no memory effect. Therefore, ample iodide ions were first added to sample solutions; the formed mercury-iodide complex was then reduced to elemental mercury using an on-line chromium(II) reduction system. The present method can be used to determine mercury at the pg 1- I level in aqueous samples without any interference from coexisting iodide ions at a level as great as 100 mg 1-1. - Anal. Sci. 8, 857-861 (1992). Fac. Pharm. Sci., Univ., Sho-machi, Tokushima 770 (J) The determination of mercury at ultratrace levels using an automated amalgamation technique. S. Mc Intosh. To investigate ultratrace determination of Hg in environmental samples, a method combining flow injection cold vapor AAS with the amalgamation technique is developed. The mercury is collected onto a gold gauze, the gauze is heated and the liberated mercury is swept into a quartz ceil located in the sample compartment of a flame AAS. The flow injection valve is used to control the mercury deposition onto the gold gauze thereby minimizing carryover effects from contaminated reagents and concentrated samples. The detection limit obtained with an 8.5 m1 sampie volume is 2 ng/1 Hg. - At. Spectrosc. 14, 4 7 - 4 9 (1993). Perkin-Elmer Corp., Norwalk, CT 06859-0219 (USA) Screen-printed electrodes for stripping measurements of trace mercury. J. Wang and B. Tian. The performance of disposable screen-printed electrodes for on-site quantitation of low mercury levels is described. Results comparable to those obtained with conventional gold electrodes can be achieved with screen-printed carbon-strip electrodes, coated with a thin gold film. Various experimental variables have been optimized to yield low detec-

175 tion limits (e.g. 0.5 gg 1-1 mercury for 4 rain deposition) and good precision (e.g., R.S.D. of 2.5% for 20 repetitive measurements of 25 pg 1-1 mercury). Applicability to trace measurements of alkyl mercury and selenium is also demonstrated. - Anal. Chim. Acta 274, 1 - 6 (1993). Dept. Chem., Univ., Las Cruces, NM 88003 (USA)

Determination of mercury at electrodes modified with polymeric films of [Ru(v-bpy)3]2+ incorporating amino acids. S.K. Cha, B.K. Ahn, Jung-Ui Hwang and H.D. Abruna. The use of electrodes modified with tryptophan, 6-aminohexanoic acid, 4-aminobutyric acid, picolinic acid, and nicotinic acid as ligands (incorporated by ion exchange into a polycationic film of electropolymerized [Ru(v-bpy)3] 2+) have been described for the determination of mercury in solution. The redox response of the surfaceimmobilized mercury/Iigand complex was used as analytical signal. In all cases, calibration curves (log of the surface coverage-normalized redox response vs log [Hg]) exhibited an excellent correlation (r _> 0.99) for mercury concentrations ranging from about 1 x 10 -8 to 1 x 10 -1 M and a relative standard deviation of 5 - 1 0 % . The relative strength of coordination exhibited in solution was retained for the surfaceimmobilized ligands. - Anal. Chem. 65, 1564-1569 (1993). Dept. Chem., Kyungnam Univ., Masan, 630-701 Korea Sequential extraction-spectrofluorimetric determination of mercury using cryptand ethers. E. Andfes, E. Fuente and D. Blanco. A rapid, simple, reproducible and selective method is developed for the spectrofluorimetry of mercury with 1,2-dichloroethane as an ion-pair formed between the cryptand 2.2.1-mercury complex and the eosinate counter-ion. The detection limit for mercury is 0.7 ng/ml, and the linear working range up to 125 ng/ml of mercury. The relative standard deviation is 2.0% at the 100 ng/mI level. The proposed method has been tested for the determination of mercury in coal. - Anal. Lett. 26, 1037 1048 (1993). Dept. Quire. Fis. Anal., Fac. Quire., Univ., Oviedo (E) Determination of copper and cadmium using an on-line anodie stripping voltammetry flow cell with detection by inductively coupled plasma mass spectrometry. J.R. Pretty, E.A. Blubaugh, E.H. Evans, J.A. Caruso and T.M. Davidson. Modifications to the system manifold of the ASV-ICP-system have been investigated. An on-line anodic stripping voltammetry flow system was used to deposit copper and cadmium from NIST-SRM 2670 Toxic Metals in Freeze-Dried Urine at a working electrode, with release of the analyte for detection by ICP-MS after the sample matrix was cleared from the cell. Recoveries determined against calibration graphs and by the method of standard additions were 94-115% for copper and 8 9 97% for cadmium. Spike recoveries for both analytes ranged from 92 106%. Elimination of the sodium-based polyatomic species at m/z = 62 and 63 remains highly efficient for up to 1 x 104 gg cm 3 of sodium, whereas the use of dilute nitric acid as electrolyte gives far superior results for copper than those previously reported. - J. Anal. At. Spectrom. 7, 113/-1137 (1992). Dept. Chem., Univ., Cincinnati, OH 45221-0/72 (USA) Simultaneous determination of copper, nickel, lead, cobalt and cadmium by adsorptive voltammetry. Zheng-Qi Zhang, Sheng-Zong Chen, HuiMin Lin and Hong Zhang. A sensitive voltammetric determination of Cu, Ni, Pb, Co and Cd is possible using the metal complexes with 1-(2-pyridylazo)-2,7dihydroxynaphthalene (2,7-PADN). In pH 9.80 buffer solution the complexes of Cu, Ni, Pb, Co and Cd with 2,7-PADN give sensitive adsorption polarographic waves at - 0.35, - 0.45, - 0.49, - 0.60 and -0.67 V, respectively, which can be used to determine trace amounts of these elements, the detection limits being 8.0, 5.0, 2.5, 0.5 and 5.0 nM, respectively. - Anal. Chim. Acta 272, 227-232 (1993). Dept. Chem., Chem. Engin., Hunan Univ., Changsha 4/0082 (RC) Capillary gas chromatographic determination of copper and nickel using microwave-induced plasma atomic emission detection. M.Y. Khuhawar, A. Sarafraz-Yazdi and P.C. Uden. The use of capillary GC coupled with FID or MIP-AED for the effective separation and quantitative determinations of copper and nickel

176 as metal chelate complexes has been tested using four tetradentate 13ketoamine reagents. Complete separation between copper and nickel complexes was obtained in each case. The chelates were also evaluated for simultaneous, selective and sensitive spectral detection of copper and nickel at 325 and 301 nm, respectively, using microwave-induced plasma atomic emission detection. The selectivity of copper at 325 nm with respect to nickel was high; some response of copper at the nickel emission line was observed, but it did not interfere with the determination of nickel. The reagent Hz(pnAA~) was used for the analysis of copper and nickel in an ore sample. The detection limits for both copper and nickel were 0.8 pg reaching the detector. - J. Chromatogr. 636, 271-276 (1993). Dept. Chem., Lederle Graduate Res. Tower A, Univ., Amherst, MA 01003 (USA) Voltammetric determination of gold using a carbon paste electrode modified with thiobenzanilide. Xiaohua Cai, K. Kalcher, C. Neuhold, W. Diewald and R.J. Magee. Gold(III) can be preconcentrated from acidic solution on a carbon paste electrode chemically modified with thiobenzanilide under opencircuit conditions. Using cathodic differential pulse voltammetry, 0.05 6 ~g ml- ~ of gold can be determined after preconcentration for 1 or 2 rain. Except for mercury(II) and platinum group metals, common ions have little effect on the determination of gold(III). The preparation and regeneration of the modified electrode were investigated. The method was used for the determination of gold in mining waste water and pharmaceutical products. - Analyst 118, 53 57 (1993). Inst. Anal. Chem., Karl-Franzens-Univ., A-8010 Graz Surfactants in spectrophotometric metal determination with 5-Br-PADAP. Sensitive spectrophotometric determination of silver with dodeeylsulphate (SDS). M. Jarosz, S. Oszwatdowski and Z. M~trczenko. The conditions for the formation of ternary complexes of selected metal ions: V(V), Ni, Cu(I), Cu(II), Pd, Ag, Cd, Hg(I), Hg(II), Tl(I), and TI(III) with 5-Br-PADAP and surfactants: sodium dodecylsulphate, Triton X-100 or zephiramine have been examined. The sensitive (~ = 6.0x 104 1 tool -1 cm -~ at ~ = 540 nm) and precise method for the determination of microgram amount of silver, based on ternary Ag-(5Br-PADAP)-SDS system has been developed (with preliminary separation of silver by electrolysis and sequestration of interfering metals by EDTA). By means of the developed procedure the silver content was determined in hydrated copper sulphate p.a. (5.8 x 10 5 %) and in copper alloy (9.7 x 10 -3 %). - Chem. Analit. 37, 335-341 (1992). Dept. Anal. Chem., Techn. Univ., 00-664 Warszawa (PL) Removal of heteropolyanions interference in the atomic absorption determination of silver and gold. A.M. Abdallah, M.S. E1-Shahawi, M.M. E1Defrawy and E.E. Askar. The harmful effect of heteropolyanion (HPA) formation on the atom population of the coinage metals, Ag and Au in the flame has been investigated. The effect can completely be eliminated by adding an excess of cyanide, resorcinol, ethylenediamine or EDTA or preparing the aspirated solution at low hydrogen ion concentration. Digestion, solvent extraction, thin layer chromatography and UV-visible measurements revealed that the HPA entities are packed together to form crystals with irregular surfaces and large cavities which permit the insertion of the analyte in these cavities. - Chem. Analit. 37, 589-598 (1992). Dept. Chem., Fac. Sci., Univ., Mansoura (ET) Determination of silver(I) in strongly complexing media by means of potentiometric titration with sodium diethyldithiocarbamate (NaDDTC). M. Mojski, M. Jarosz and I. Gtuch. The potentiometric titrations of AgO) with NaDDTC in strongly complexing media (containing ammonia, sulphite, thiocyanate or thiosulphate) is investigated. The use of a sulphide ion-selective electrode ensures a well-defined potential break on the titration curves. The method reported here has been applied to the determination of silver in waste fixers and photographic film. The relative standard deviations do not exceed I%. - Analusis 20, 567-571 (1992). Dept. Anal. Chem., Techn. Univ., 00-664 Warsaw (PL)

1 General analytical methods Selective kinetic determination of traces of gold by eleetrodeposition on a piezoelectric detector. C. Sanchez-Pedrefio, J.A. Ortufio and D. Martinez. To determine gold in minerals a sensitive method which is based on its electrodeposition on a gold-plated quartz piezoelectric crystal is developed. Under the selected conditions the slope of the frequency versus time plot is proportional to gold(III) concentration in the range 0.15-2.50 gg m1-1 with a slope of 380 Hz rain -1 lag-1 ml and a correlation coefficient of a 999 (n = 10). The relative standard deviations for 2.0 and 0.3 lag ml-1 obtained by withdrawing and immersing the sensor were 2.2 and 5.0%, respectively. The deposit does not need to be removed after each measurement, which makes the method very rapid. Of the 21 metal ions tested, only Ag(I), Hg(II), Pt(IV) and Pd(II) are also electrodeposited and their interferences can be avoided by previous extraction of the gold(III) chloro complex into diethyl ether. The method was applied satisfactorily to the determination of gold in minerals with a low gold content. - Anal. China. Acta 263, 143 146 (1992). Dept. Anal. Chem., Fac. Sci., Univ., 30071 Murcia (E)

Extraction and spectrophotometric determination of rhodium(III) with isonitroso-p-methylacetophenone. H.A. Mahajan and M.R. Patil. Rhodium(III) can be extracted quantitatively (99.4%) with isonitrosop-methylacetophenone (HIMAP) into chloroform at pH 4.2-6.5 after heating on boiling water-bath for 30 min. Beer's law is obeyed over the Rh(III) range 0.05-6 gg ml- ~ at 370 nm. The molar absorptivity and Sandell sensitivity are 2.47 x 104 1mol - 1 cm ~ and 4.2 ng cm- z respectively. Mean of 10 determinations of 5 ixg of Rh(III) is 4.94 lag, which varies between 4.81 to 5.07 lag at 95 % confidence interval and standard deviation is 0.19 lag. The composition of extracted species is found to be 1:3 (Rh:HIMAP). The proposed method has been applied for the determination of Rh(III) in synthetic mixtures. - Chem. Analit. 37, 239-243 (1992). Dept. Chem., Inst. Sci., Bombay-400032 (IND)

Adsorptive differential-pulse voltammetric determination of trace amounts of ruthenium. R. Palaniappan and T. Ashok Kumar. Trace amounts of ruthenium can be electrochemically determined by a method based on the adsorptive accumulation of Run-salicylaldehyde thiosemicarbazone on the surface of a hanging mercury drop electrode, followed by the reduction of the adsorbed complex during the cathodic scan. The adsorptive differential-pulse voltammetric curve exhibited a well-defined cathodic peak at -0.750 V versus a saturated calomel electrode. The optimum analytical conditions for the determination of ruthenium, for the working range 5 - 80 ng cm-3, were established. A statistical evaluation of the experimental results is reported. - Analyst 118, 293-296 (1993). Appl. Develop. Lab., Electrochem. Spectr. Div., Elico Pvt. Ltd., Sanath Nagar Ind. Est., Hyderabad-500 018 (IND)

Effect of surfactant on the spectrophotometric determination of palladium complexed with 4-nitrobenzenediazobenzene and 1,10-phenanthroline. Y. Zhu and Li Yang. Pd(II) can be determined sensitive and selective by reaction with 1,10-phenantroline and 4-nitrobenzenediazobenzene (Cadion A) in the presence of the non-ionic surfactant Peregal 0 to form a stable complex. The maximum absorption of the complex ist at 490 nm, its apparent molar absorptivity is 8.01 x 104 l-tool-~.cm-1. Beer's law is obeyed for Pd in the range of 0 - 2 0 pg/25 ml, with EDTA and sodium potassium tartrate as masking agents, common ions do not interfere. The method has been used in the determination of palladium in Pd containing catalysts without separation. - Anal. Letters 26, 309-323 (1993). Dept. Chem., Hangzhou Univ., Hangzhou, 310028 (RC)

Thin-layer chromatographic determination of inorganic anions as counterions of metal-diantipyrilmethane cationic complexes and diantipyrilmethane cations. O. Shadrin, V. Zhivopistsev and A. Timerbaev. Some common inorganic anions can be separated as metal diantipyrilmethane (DAM) complexes by TLC with organic solventmineral acid or binary organic solvent mixtures using the ascending or

1.3

177

Organic analysis

radial chromatographic technique. The chromatographic zones can be easily detected, being highly coloured (iron complexes) or fluorescent under UV light (terbium complexes). A procedure was developed for a simple, fast and comparatively sensitive determination of inorganic anions in water samples, based on liquid extraction of their diantipyrilmethane salts from the aqueous analysis sample. - Chromatographia 35, 667 670 (1993). Dept. Anal. Chem., Univ., 614000 Perm' (Russian Federation)

Spectrophotometric determination of nitrogen dioxide (nitrite). D.C. Parashar, M. Singh, N. Singh and A.K. Sarkar. To determine NO2 (NO2 as NO2) NO2- was treated with excess of MnO2 in 1:20 HC104 where NQ2- reduces equivalent amounts of Mn(IV) to Mn(II) and becomes soluble. The soluble Mn(II) ion is filtered to remove excess of MnO2 and is oxidized to permanganate ion by periodic acid in presence of phosphoric acid. The violet colored solution shows maximum absorbance at 525 nm. The sensitivity of the method is 0.08 ppm based on 0.0044 absorbance, and Beer's law is obeyed in the concentration range of 0.2 to 10.0 gg/ml of NO2 . Molar absorbance is found to be 2442 at 525 nm. - Anal. Lett. 26, 959-963 (1993). Anal. Chem. Sect., Nat. Phys. Lab., New Delhi - 110 012 (IND) Simultaneous determination of iodide and nitrite by catalytic kinetics. Zhong-liang Zhu and Zhi-cheng Gu. Nitrite and iodide can be determined simultaneously in one run using their kinetic effect on the colour fading of the iron(II)-thiocyanate complex in nitric acid solution. The rate of the colour-fading reaction is linearly related to the concentration of iodide and is independent of the concentration of nitrite. The length of the induction period of the indicator reaction is inverse to the logarithm of the concentration of nitrite and is independent of the concentration of iodide. With 1.3 tool I- 1 HNO3, 0.067 tool 1-1 Fe 3÷ and 2 . 7 x i 0 -* tool 1- I SCN-, concentrations of 4 . 0 × 1 0 - 5 - 1 . 6 x 1 0 -4 tool 1-1 iodide and 4.1×10 7 6.6 x 10 -6 tool 1 1 NO2- were determined with mean relative errors of 1.5 and 3.9%, respectively. - Analyst 118, 105-108 (1993). Dept. Chem., Tongji Univ., Shanghai 200092 (RC) Gas chromatographic determination of trace nitrite after derivatization with ethyl 3-oxobutanoate. T. Mitsuhashi. A simple and sensitive GC method was developed for the determination of nitrite using ethyl 3-oxobutanoate as a derivatization reagent. Nitrite was reacted with ethyl 3-oxobutanoate in the presence of hydrochloric acid to form ethyl 2-hydroxyimino-3-oxobutanoate (EHOB) quantitatively. The resulting EHOB was extracted with ethyl acetate and then determined by GC/ECD using a HP-1 capillary with a temperature programme from 60 to 200°C. This method has been applied successfully to the determination of nitrite in river water and human saliva, with a detection limit of 2 ng/ml and recoveries of 94-100%. - J. Chromatogr. 629, 339-343 (1993). Hyogo Prefect. Inst. Publ. Health, Arata-cho, Hyogo-ku, Kobe 652 (J) Preconcentration and determination of trace permanganate, chromate and molybdate ions, using an ion-exchanger (cellulose-Hyphan) and atomic absorption spectrometry. I.M.M. Kenawy, M.M. E1-Defrawy, M.Sh. Khalil and K.S. El-Said. The use of a cellulose ion-exchanger (Hyphan) for the isolation of MnO4-, CrO42- and MoO42- from aqueous solution after reduction with different reducing agents is described. After preconcentration, Mn(lI), Cr(III) and molybdenum cations were determined by AAS. A concentration factor of 500 could be achieved. The interfering effects of different foreign ions were studied. An analytical application for the preconcentration and separation by cellulose-Hyphan and determination of metaI ions studied in tap, Nile, waste and sea water was carried out. - Anal. Lett. 26, 1227-1242 (1993). Chem. Dept., Fac. Sci., Univ., Mansoura (ET) Amperometric and fast scan-rate cyclic voltammetry detection at a microelectrode for gel permeation high-performance liquid chro-

matography of fullerenes. B. Soucaze-Guillous, W. Kutner and K.M. Kadish. The first application of an electrochemical detection method for the determination of fullerenes after gel-permeation HPLC is described. A toluene extract of the laser-vaporized soot containing low molecular mass fullerenes was resolved on two gel permeation columns in series. The mobile phase was dichloromethane/cyclohexane, 90/10 (v/v), 0.01 M tetra-n-butylammonium perchlorate. The number and shapes of the peaks in chromatograms obtained with amperometric detection at - 1.3 V vs. SCE were the same as those obtained with UV-visible spectroscopic detection at 365 nm, thus indicating that all of the detected compounds both absorb UV-visible light and are electrochemically active. Extracolumn peak broadenings due to detection and detectability (83.8 ng for C60) were also the same in both detection techniques. In situ fast scan-rate voltammograms of C60 and Cv0 were obtained during elution, and the reversible E1/2 values of the third and fourth electroreductions could be used for their identification. - Anal. Chem. 65, 669-672 (1993). Dept. Chem., Univ., Houston, TX-77204-5641 (USA) Separation of fullerenes C60, C70, and C76-s4 on polystyrene divinylbenzene columns. D.L. Stalling, K.C. Kuo, C.Y. Guo and S. Saim. HPLC methods have been developed to effictively separate and recover essentially pure amounts of C60 and C70 fullerenes from the lower MW contaminants and higher MW fullerenes co-extracted from carbon soot. Separation with toluene/methylene chloride mobile phase is investigated. The presence of either toluene or CS2 in the mobile phase attenuates ~-electron interactions. The separation mechanism becomes predominantly size exclusion chromatography for a CS2 concentration in the mobile phase _> 60%. Excellent separation of C60, C70 and C76-s, is obtained with the analytical Envirosep-ABCTM columns in less than 15 min. An optimized set of columns consisting of a guard column (60 x 21.2 mm) and a modified preparative column (350 × 21.2 ram) with improved flow design and separation efficiency is proposed. - J. Liquid Chromatogr. 16, 699-722 (1993). ABC Lab., Columbia, MO-65205 (USA) High-performance liquid chromatographic separation of fullerene mixtures using a novel stationary phase. M.R. Banks, I. Gosney, A.C. Jones, D.S. Jones, P.R.R. Langridge-Smith, R.J. McQuillan and P. Thorburn. Fullerenes in the range of C6o to Cloo can be separated on the novel stationary phase Fullerene Sep with hexane, which have advantages in comparison to the expensive "Pirkle-type" columns. - Chromatographia 35, 631 - 636 (1993). Dept Chem., Univ., Edinburgh, EH9 3JJ (GB)

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Organic analysis

Tandem mass spectrometry of very large molecules. 2. Dissociation of multiply charged proline-containing proteins from electrospray ionization. J.A. Loo, C.G. Edmonds and R.D. Smith. A short review considering 80 references is given for collisional dissociation tandem mass spectra for multiply charged molecules produced by electrospray ionization for a variety of proline-containing proteins extending up to 22000 molecular weight. Interpretation of limited m/z range, low-resolution tandem mass spectra from multiply charged precursors can present difficulties due to the possibility of multiply charged product ions and the lack of unambiguous charge state information. Methods used to guide the spectral interpretation process under these circumstances are discussed. - Anal. Chem. 65,425 -438 (1993). Chem. Sci. Dept., Pac. Northwest Lab., Richland, WA 99352 (USA) High-temperature gas-chromatographic headspace-analysis of volatile polar impurities in aqueous solutions. A.G. Vitenberg, N.V. Novikaite and M.I. Kostkina.

] 78 Polar, freely water-soluble impurities as phenols can be determined in aqueous media by high-temperature headspace analysis under static conditions above 100°C. The sensitivity of gas chromatographic determination of volatile phenols in aqueous solutions was increased 2 0 - 1 0 0 fold and the detection threshold was reduced to 10 gg x 1-1 Preliminary concentration by high-temperature microdistillation at elevated pressure is useful. A theoretical model of this process has been developed. The possibility of concentrating volatiles by high-temperature microdistillation has been experimentally confirmed. - Chromatographia 35, 661 666 (1993). Lab. Gas Chromatogr., Chem. Dept., Univ., 198904 St. Petersburg (Russia) CS2 charge exchange as a low-energy ionization technique for hydrocarbon characterization. Chang S. Hsu and Kuangnan Qian. Charge exchange using CS2 as reagent gas (CSz/CE) has been studied concerning hydrocarbon characterization in comparison to low-voltage EI-ionization (LV/EI). CS "÷ ions formed under low-energy electron ionization conditions readily undergo charge-exchange reactions with hydrocarbons having ionization potential less than 9.5 eV. Small variations in electron beam energies do not affect the relative yields of the molecular ions. Higher sensitivities in CS2/CE over LV/EI facilitate highresolution accurate mass measurements. Uniform sensitivities over a wide range of compound types eliminate the need for calibration compounds for the quantitative determination of the components in a hydrocarbon mixture. - Anat. Chem. 65, 767-771 (1993). Exxon Res.. and Eng. Comp., P.O. Box 998, Annandale, NJ-08801 (USA) Simultaneous analysis of carbon oxides and hydrocarbons by gas chromatography-mass spectrometry. R.T. Talasek and K.E. Daugherty. For the simultaneous determination of carbon monoxide, carbon oxide, and C1 - C 4 hydrocarbons GC/MS is used. CO is trapped at room temperature on a Molesieve PLOT column, while determination of other species is performed on a PoraPLOT Q column. Carbon monoxide is then eluted at an elevated temperature. Detection limits in the low gg m -3 regime are reported with a linear dynamic range that permits analysis in the mg m - 3 range. No interferences between analytes or with air components are reported. - J. Chromatogr. 635, 265-270 (1993). Dept. Chem., Univ., Denton, TX (USA) Radical analysis in the pyrolysis of hydrocarbons by scavenging with dimethyl disulfide. K. Guthier, P. Hebgen, H.P. Loock, K.H. Homann, G. Zimmermann and J. Hofmann. Radicals formed in the low pressure pyrolysis of hydrocarbons can be quantitatively analyzed by scavenging them with dimethyl disulfide (DMDS) in the condensed phase. The pyrolyses of several hydrocarbons (ethyne, ethene, 1.3-butadiene, and benzene) have been studied in a flow reactor at 1300 K and 10.7 mbar. For the analysis of the radicals formed during the pyrolysis, a part of the hot gases at the end of the reactor is proped continuously by a quartz probe, the resulting supersonic nozzle beam was frozen together with an excess of DMDS on the inner surface of two hollow hemispheres coded by liquid nitrogen. While melting the scavenging reaction takes place. The mixture of DMDS, stable pyrolysis products, and methylthio compounds was separated and identified with a GC-MS-system. CHa', CzH3", C6H5" radicals and H-atoms have been detected. - Ber. Bunsenges. Phys. Chem. 97, 140-141 (1993). Inst. Phys. Chemic der Techn. Hochsch. Darmstadt, Petersenstral3e 20, W6100 Darmstadt (D) Cyclodextrin stationary phases for the gas-solid chromatographic separation of light hydrocarbons. Evidence for multiple retention mechanism. G.L. Reid, III, C.A. Monge, W.T. Wall and D.W. Armstrong. Cyclodextrin bonded to silica gel offers a practical and efficient means for separating a wide variety of volatile Ca - C7 hydrocarbons at ambient to elevated temperatures. Conditioning the columns at high temperature (300°C) for several hours increased efficiency and resolution. For unsaturated hydrocarbons, the cyclodextrin GSC column can act as a polar stationary phase analogous to silica gel; for saturated hydrocarbons, it acts as a non-polar phase. Evaluation of the columns and an analogous silica gel column with hydrocarbon standards is reported. Capacity factors and chromatograms are presented for compounds analyzed on

1 General anaiytical methods these GSC stationary phases. - J. Chromatogr. 633, 135-142 (1993). Dept. Chem., Univ., Rolla, MO 65401 (USA) Enzymatic determination of alcohol mixtures at the nanogram level by the stopped-flow technique. E. F6rster, M. Silva, M. Otto and D. P~rezBendito. Dilute solution of lower straight-chain alcohols react with alcohol dehydrogenase in the presence of the coenzyme I3-NAD + time-dependent to form the corresponding aldehyde and NADH, which can be monitored at 340 nm at 340/460 nm, respectively. Methanol, ethanol, propanol and butanol can thus be determined over the range 3.0 x 10 -8 - 1.0 x 10 -6 M with a relative standard deviation of ca. 1.2 3.8%. Spectrofluorimetric measurements are better suited to the individual determinations, whereas spectrophotometric measurements are more useful for resolving alcohol mixtures using the Kalman filter algorithm. Mixtures of methanol-butanol, ethanol-butanol and methanol-propanol at the submicromolar level were successfully resolved with errors of less than 10 %. - Anal. Chim. Acta 274, 109 - 116 (1993). Inst. Anal. Chem., Bergakademie, 9200 Freiberg (D) Analysis of multi-component mixtures by high-resolution capillary gas chromatography and combined gas chromatography-mass spectrometry. II. Trace aromatics in an n-alkane matrix. E. Matisovfi, S. Vod@, S. Skrab~kovfi and M. Onderov~. A multicomponent organic mixture with components present in trace concentrations in a complex sample matrix can be analysed using a single-column separation system with splitless injection in capillary GC and GC-EI-MS after a preseparation step. - J. Chromatogr. 629, 309 320 (1993). Dept. Anal. Chem., Fac. Chem. Technol., Techn. Univ., 812 37 Bratislava (Slovakia) Chromatographic determination of position and configuration isomers of methyl oleate hydroxides from corresponding hydroperoxides. R. Bortolomeazzi, L. Pizzale and G. Lercker. Methyl oleate hydroxy-octadecenoates derived from methyl oleate hydroperoxides can be separated in the cis- und trans-fraction by TLCAgNO3; the fraction can be analyzed by HPLC to determine the quantitative distribution of the OH-group's positional isomers and by GC/MS to identify the isomers. - Chromatographia 36, 6 1 - 6 4 (1993). Dip. Tecnol., Chim. Microbiol. Agro., Univ., 33100 Udine (I) Gas chromatographic analysis of alkanolamine solutions using capillary and packed columns. O.F. Dawodu and A. Meisen. Supelcowax 10, a capillary column liquid lined with polyethylene glycol can be used instead of Tenax packed columns for the GC of fresh and partially degraded alkanolamine solutions. The capillary column provides better peak shape, requires significantly less sample size, maintains higher sensitivity and offers a faster and more efficient separation than the Tenax packed columns. - J. Chromatogr. 629, 297 - 307 (1993). Dept. Chem. Engin., Univ., Vancouver, BC V6T 1Z4 (CDN) Electrochemiluminescence detection of primary amines using tris(bipyridine)ruthenium(III) after derivatization with divinylsulfone. K. Uchikura, M. Kirisawa and A. Sugii. A selective, sensitive detection of primary amines, amino acids, polyamines and other biological amines is developed which is based on the fluorescence by the cyclo-addition reaction of the amines with divinyl sulfone caused by electrogenerated Ru(bpy)33 +. The derivatization reaction rapidly produced high fluorescence yields under conditions as mild as pH 8 and 50°C. By combining HPLC with post-column derivatization the amines could be determined in a wide variety of complex biological samples. = Anal. Sci. 9, 121--123 (1993). Coll. Pharm., Nihon Univ., Narashinodai, Funabashi 274 (J) Potentiometric discrimination of organic amines by a liquid membrane electrode based on a lipophilic hexaester of calix[6]arene. K. Odashima, K. Yagi, K. Tohda and Y. Umezawa. A new mode of potentiometric discrimination of organic guests is reported, which is based on the recognition of steric shapes of nonpolar moieties by inclusion into the new lipophilic hexaester of calix[6]arene. PVC was used as matrix liquid membrane electrode. The strongest re-

1.3

Organic analysis

sponses were observed towards primary amines having no substituent adjacent to the amino group such as l-octylamine, 2-phenylethylamine, and dopamine. - Anal. Chem. 65, 1074-1083 (1993). Dept. Chem., Fac. Sci., Hokkaido Univ., Sapporo, Hokkaido 060 (J) HPLC-based method for determination of absolute configuration of ~chiral amines. P.A. Husain, J. Debnath and S.W. May. To determine the absolute configuration of c~-chiral amines including amino acid derivatives the chiral compounds are derivatized with Nsuccinyl-~-methoxyphenylacetate (SMPA) resulting in the corresponding diastereomeric adducts which can be separated by HPLC. No enantiomeric standard is needed to obtain the absolute configuration. The methods can be used advantageously in comparison to NMR. A particular rotomer of the used SMPA adduct and the corresponding HPLC elution order gives information about the absolute configuration using simple rules. - Anal. Chem. 65, 1456-1461 (1993). School Chem., Biochem., Georgia Inst. Techn., Atlanta, GA 30332-0400 (USA) Chiral recognition of enantiomeric amides on a diamide chiral stationary phase by gas chromatography. Xianwen Lou, Xueliang Liu and Liangmo Zhou. The chiral separation factors (et) are determined for several ~-alkyl-, :~-cycloalkyl- and c~-aromatic-substituted ethylamine enantiomers on a cross-linked polycyanoethyl vinyl siloxane/L-valine/tert.-butylamide fused-silica capillary column. Kovfits retention indices of cyclohexane, benzene, anisole and the derivatized amines on the chiral stationary phase (CSP) were determined and compared with those on SE-30. By extrapolation of the retention behaviour, the chiral recognition mechanism of enantiomeric amides on diamide CSPs is discussed. - J. Chromatogr. 634, 3 4 5 - 349 (1993). Inst. Chem. Phys., Acad. Sci., Dalian 116012 (RC) Oxazole-based tagging reagents for analysis of secondary amines and thiols by liquid chromatography with fluorescence detection. T. Toyo'oka, H.P. Chokshi, R.G. Carlson, R.S. Givens and S.M. Lunte. A series of halogeno-diaryl-oxazoles were used as fluorescent labelling reagents for the determination of secondary amines and thiols after LCseparation. The spectroscopic characteristics, stability and chromatographic behaviour of the compounds labelled with 2-fluoro-4,5-diphenyloxazole (DIFOX), 2-chloro-4,5-diphenyloxazole (DICLOX) and 2chloro-4,5-bis(p-N,N-dimethylaminosulfonyl)oxazole (SAOX-C1) are given. Emission maxima for the diphenyloxazole (DIOX) and SAOX derivatives of amines were 420 nm ()~ex 320 nm) and 485 nm ()~ox 360 nm), respectively. The emission wavelengths for the DIOX- and SAOXthiols are 390 nm ()~ox310 nm) and 425 nm ()~ex330 nm), respectively. SAOX-C1 was used for the determination of thiols and DIFOX was employed for amines in all subsequent studies. Detection limits (signalto-noise ratio = 2) for authentic DIOX-amines ranged from 3.7 to 28.4 fmol, and SAOX-thiols ranged from 1.2 to 1.9 fmol. - Analyst 118, 257-263 (/993). Cent. Bioanal. Res., Univ. Kansas, Lawrence, KS 66047 (USA) Thin-layer chromatography of aliphatic thiols after fluorescent labelling with methyl 4-(6-methoxynaphthalen-2-yl)-4-oxo-2-butenoate. P. Roveri, V. Cavrini, V. Andrisano and R. Gatti. Aliphatic thiols of biopharmaceutical (cysteine, N-acetylcysteine, homocysteine, captopril, glutathione, mercaptopropionylglycine) and cosmetic (thioglycolic acid, monothioglycerol, ammonium thiolactate) interest react under mild reaction conditions (10 rain at room temperature) with methyl 4-(6-methoxynaphthalen-2-yl)-4-oxo-2-butenoate to give fluorescent adducts which can be separted on TLC silica gel plates using chloroform/methanol/acetic acid mixtures as mobile phases. The fluorescent spots are visualized on irradiation at 254 and 366 n m . - J. Liquid Chromatogr. 16, 1859-1866 (1993). Dipt. Sci. Farm., 40126 Bologna (I) Selective detection of free thiols by capillary electrophoresis-electrochemistry using a gold/mercury amalgam microelectrode. T.J. O'Shea, S.M. Lunte. An extremely sensitive thiol-specific detector for capillary electrophoresis and other microcolumn separations which employs a gold/mercury

] 79 amalgam microelectrode has been developed. The detection method is based on the catalytic oxidation of mercury in the presence of thiols. Detection limits for glutathione are 0.53 fmol (or 2.1 x l0 -~ M). Deoxygenation of the system was important for reproducibility of response. Under deoxygenated conditions, the RSD for 20 injections was 2.1%. The electrode can easily be regenerated in situ by electrodeposition or by removing and dip-coating with mercury. The use of this method for the separation and detection of a number of biologically important thiols is reported. - Anal. Chem. 65, 247--250 (1993). Cent. Bioanal. Res., Univ. Kansas, Lawrence, KS 66047 (USA) Capillary zone electrophoresis of organic acids and anions. L. Kelly and R.J. Nelson. Small organic anions are separated by CZE and monitored by indirect detection. Two buffer systems are described for the separation of anions by capillary electrophoresis. Organic acids are separated with potassium hydrogen phthalate, 2-(N-morpholino)-ethanesulfonic acid and tetradecyltrimethyl ammonium bromide. Other anions are separated in 1,2,4,5 benzene tetracarboxylic acid (pyromellitic acid) and diethylenetriamine. The selectivity and the speed/~f the analysis is temperature-dependent. - J. Liquid Chromatogr. 16, 2103-2112 (1993). Spectra-Physics Anal., Inc., 45757 Northport Loop West, Fremont, CA 94537-5116 (USA) Determination of picomole amounts of carbonyls as luminarin hydrazones by high-performance liquid chromatography with fluorescence detection. F. Traor6, G.A. Pianetti, L. Dallery, M. Tod, J. Chalom, R. Farinotti and G. Mahuzier. Luminarin 3, luminarin 11 and luminarin 12, having a quinolizinocoumarin moiety as fluorophore and a carboxylic acid hydrazide function as reacting group are highly sensitive fluorescence derivatization reagents for aldehydes and ketones in HPLC. They react with carbonyl compounds in aqueous sulphuric acid solution (0.1 M) at room temperature to the corresponding hydrazone derivatives, which can be separated on both reversed or normal-phase column. The detection limits (signal to noise ratio = 3) for aldehydes and ketones were in the sub-pmol range. Luminarin 3 was also applied to the determination of hydroxymethylfurfural (HMF) in orange juices and concentrates. The method for HMF involves the solid-liquid extraction of the juice by using a C-18 cartridge prior to derivatization and normal-phase separation of the derivative with fluorimetric detection at 387 nm/444 nm. The calibration curve was linear for amounts of HMF ranging from 0./ to 10 nmol. Intrarun relative standard deviation was 12.8% for 0.1 nmol and 2.6% for 1 nmol. Recovery studies indicated an average of 98.7 __1.9% for juice concentrate and 99.8 __3.2% for pasteurized juice. - Chromatographia 36, 9 6 - 1 0 4 (1993). Lab. Chim. Anal., Fac. Sci. Pharm. Biol., Univ. ParisSud, 92290 Chatenay-Malabry (F) Gas chromatographic enantiomer separation with modified cyclodextrins: carboxylic acid esters and epoxides. W.A. K6nig and B. Gehrcke. The separation factors of a great number of chiral methyl esters obtained on capillary columns coated with 2,6-di-O-methyl-3-O-pentyl[~- and ?-cyclodextrins are given. These chiral phases were applied in 1 : 1 mixtures with polysiloxane OV-t701 at temperatures between 55 and 250°C; ~- and J3-hydroxy acids with up to 18 carbon atoms, hydroxy diand tricarboxylic acids, and alkyl/aryl-substituted carboxylic acid methyl esters, including the plant hormone abscisic acid, insect juvenile hormones, and some non-steroidal anti-inflammatory drugs can be resolved with generally large separation factors. The new cyclodextrin derivatives also exhibit high selectivity for epoxides. - J. High Resolut. Chromatogr. 16, 175--181 (1993). Inst. Org. Chem., Univ., W-2000 Hamburg 13 (D) Liquid chromatographic determination of chiral epoxides by derivatization with sodium sulphide, o-phthalaldehyde and an amino acid. A.L.L. Duchateau, N.M.J. Jacquemin, H. Straatman and A.J. Noorduin. Enantiomers ofchiral epoxides can be determined after derivatization with sodium sulphide, o-phthalaldehyde and an optically pure amino acid. Chiral mono- and 2,2-disubstituted epoxides were converted into diastereomeric isoindole derivatives. Separation of the diastereomers was carried out by HPLC on a LiChrosorb RP-18 column with 50 mM

180 sodium acetate (pH gradient)/methanol (45:55). The derivatives were detected fluorimetrically. For a series of nine monosubstituted epoxides, good enantioselectivity was obtained (~ = 1.3 - 1.7). The derivatization procedure was optimized using glycidyl butyrate as test compound. Both the precision and accuracy of the method were investigated. - J. Chromatogr. 637, 2 9 - 3 4 (1993). Dept. FA, DSM Res. BV, 6160 MD Geleen (NL) Determination of carboxylic acids by ion-exclusion chromatography with non-suppressed conductivity and optical detectors. M. Ye, K. Hill and R. Walkup. A direct conductivity detection of carboxylic acids was achieved by using mobile phases with low background conductance. Using 0.2 mM 1-octanesulfonic acid as a mobile phase and an injection volume of 300 ~1, the detection limits range from 1 gM for formic acid to l0 gM for butyric acid. The conductivity detector was connected in tandem with a Waters 484 optical detector at 210 nm, which allowed the analysis of carboxylic acids from 0.01 mM to 10 raM. The dependence of the retention of carboxylic acids on the eluent pH is discussed. Chromatographia 35, 139-141 (1993). Man Tech Environ. Techn., Inc., Ada, OK 74820 (USA) Liquid chromatographic studies for essential fatty acids on a commercial alkyl phenyl bonded silica column. C.B. Ching, K. Hidajat and M.S. Rao. Arachidonic acid, eicosatetraenoic acid, eicosapentaenoic acid and docosohexaenoic acid can be separated on a commercial gBondapak free fatty acid column isocratically with acetonitrile/water/tetrahydrofuran and differential refractometry detection. Retention data were measured at various flow rates with two different, mobile phase compositions. Capacity factors and enthalpy of adsorption were calculated from the retention data. Finally the retention mechanism is explained. Chromatographia 35, 399 402 (1993). Dept. Chem. Engin., Nat. Univ., Singapore, 0511 (SGP) Simple gas chromatographic method for the assay of salts of carboxylie acids as their trimethylsilyl derivatives. Lay-Keow Ng and M. Hup& Several potassium and sodium salts ofmonobasic, dibasic and tribasic organic acids, and sodium and calcium salts of fatty acids were directly silylated by Tri-Sil (a mixture of hexamethyldisilazane and trimethylchlorosilane in pyridine). The reaction mixture were injected directly into a gas chromatograph with a DB5 fused-silica column using a temperature program from 100 to 280°C and an FID. Identities of the derivatives were confirmed by GC-MS analysis. Carbon chain distributions of the fatty acid salts were determined by GC quantitation of the TMS derivatives formed by direct silylation of the salts and the fatty acids liberated from the salts. - J. Chromatogr. 637, 104-108 (1993). Lab. & Sci. Serv. Direct., Revenue Canada, Customs & Excise, Ottawa, Ontario K1A 0L5 (CDN) Determination of formic acid vapour using piezoelectric crystals with 4ethyl-3-thiosemicarbazide and 2,6-diacetylpyridine coatings. J.A. Mufioz Leyva, J.L. Hidalgo Hidalgo de Cisneros, D. Garcia G6mez de Barreda and A.J. Fraidias Becerra. To determine formic acid in its vapor form two sensors were developed based on AT-cut piezoelectriccrystals coated, by immersion, with films of 4-ethyl-3-thiosemicarbazide and 2,6-diacetylpyridine. The sensors have been perfected using a new static system comprising an oscillator mounted on a die-plate and placed inside a testing chamber. The sensors show their sensitivity for formic acid for at least 60 d. Selectivity is adequate with both coatings. The sensors begin to respond to formic acid vapour immediately, reaching a stable frequency after 5 rain; average recovery times are about 28 rain. For the 4-ethyl-3-thiosemicarbazide sensor, the sensitivity is 29.7 Hz mg 1 1with a correlation coefficient of 0.9997 and a detection limit of 0.17 mg 1-1. For the 2,6-diacetylpyridine sensor, the values are 10.9 Hz mg 1 1 1, 0.987 and 0.33 mg 1-1, respectively. The sensors could be used to detect formic acid vapour. The advantages over existing techniques are reduced cost and capacity for use in situ. - Analyst 118, 175-178 (1993). Dept. Anal. Chem., Cfidiz

(E) Gas chromatographic determination of sodium monofluoroacetate as the free acid ]n an aqueous solvent. B.A. Kimball and E.A. Mishalanie.

1 General analytical methods Sodium monofluoroacetate can be determined as the free acid by capillary GC/MS. Commercially available polyethylene glycol capillary columns were compatible with injections of highly acidic aqueous solutions. Using monochloroacetic acid as an internal standard, a coefficient of variation of less than 2% was routinely obtained from replicate injections of a 100 lag/ml solution of sodium monofiuoroacetate in I M HC1. The monofluoroacetic acid/monochloroacetic acid detector response ratio was a linear function of sodium monofluoroacetate concentration from 5 to 200 gg/ml. The average analyte recovery from 30 to 40 g biological samples fortified with between 2.5 and 100 mg of sodium monofluoroacetate was 81% with relative standard deviation typically less than 7%. The instrument limit of detection was 200 pg sodium monofluoroacetate when the detector was operated in the selected ion monitoring mode. - J. Chromatogr. 634, 289-296 (1993). Dept. Agricult., Animal Plant Health Insp. Serv., Wildlife Res. Cent., Federal Cent., Denver, CO 80225 (USA) Selectivity and efficiency enhancement of supercritical fluid extraction by application of reactive additives. L The analysis of calcium montanate using citric acid as a complexing agent. A. Venema and T.J. Jelink. Calcium montanate (a mixture of aliphatic hydrocarbons, fatty acid esters of C z 8 - C32 acids, the calcium salts of these fatty acids, and the acids themselves) can be selectively extracted with supercritical fluids. By use of carbon dioxide, carbon dioxide containing 10% methanol, and carbon dioxide containing 10% methanol and citric acid (as a further additive), the various compound classes could be isolated with high selectivity. The addition of citric acid results in the complexation of Ca 2+ and the simultaneous formation of the free fatty acids, which are soluble in the extractant. Reactive additives can enhance the applicability of supercritical fluids in extraction problems. J. High Resolut. Chromatogr. 16, 166-168 (1993). Akzo Res., Corp. Res. Dept., 6800 SB Arnhem (NL) Ion chromatographic method for the simultaneous determination of trifluoromethanesulfonic acid (TFMSA) and trifluoroaeetic acid (TFA). N. Simonzadeh. The toxic acids TFMSA and TFA, which are used in peptide analysis can be determined by a suppressed ion chromatographic method with conductivity detection. A Dionex anion column (AS4A) was used for all separations with 1.5 mM Na2CO3/2.5 mM NaHCO3/4% (v/v) acetonitrile as the eluent. Method validation included: standard linearity plots and standard addition-recovery data. Various inorganic trace impurities occasionally present in the peptide samples did not interfere with the determination of TFMSA and TFA. -- J. Chromatogr. 634, I25-128 (1993). Bioanal. Res. Dept., Abbott Lab., North Chicago, IL 600644000 (USA) Direct optical resolution of 3,5-substituted J-valerolactones and related 3,5-dihydroxyvaleric methyl esters on modified amylose and cellulose chiral stationary phases. A. Kunath, B. Henkel and J. Wagner. The first direct determination of the enantiomers of 3,5-disubstituted lactones and related diol esters was carried out by HPLC on chiral stationary phases consisting of cellulose tris(3,5-dimethylphenylcarbamate), cellulose tris(4-chlorophenylcarbamate) and amylose tris(3,5dimethylphenylcarbamate) derivatives coated on macroporous silica using hexane-2-propanol and hexane/ethanol mobile phases. In most instances baseline separation could be achieved. - J. Chromatogr. 634, 119 - 124 (1993). Cent. Select. Org. Synth., O-1199 Berlin-Adlershof(D) Sensor-array for carbohydrates and amino acids based on electrocatalytic modified electrodes. Qiang Chen, J. Wang, G. Rayson, B. Tian and Y. Lin. The operation and advantages of a novel amperometric sensor array based on the use of catalytic chemically modified electrodes is described. Different metal oxide catalysts are used to dope carbon paste electrodes. The Cu20-, RuO2-, NiO-, and CoO-modified surfaces exhibit distinctly different catalytic properties toward carbohydrates or amino acids. By coupling the unique sensor array response patterns with various statistical regression techniques, it is possible to determine individual carbohydrates or amino acids in different sample mixtures. For two- and three-component mixtures, the partial least squares (PLS) calibration

1.3

Organic analysis

method yields an average relative prediction error of 2.3%. Such multicomponent quantitation is accomplished in amperometric flow injection experiments. The response is highly stable and linear. - Anal. Chem. 65, 251-254 (1993). Dept. Chem., New Mexico State Univ., Las Cruces, NM 88003 (USA)

Separation and detection of underivatized amino acids. P.G. Simonson and D.J. Pietrzyk. Amino acids (AA) can be separated on a Hamilton PRP-1 polystyrene divinylbenzene column with a basic CHaCN/H20 mobile phase containing a tetraalkylammonium (R4N +) salt and a detector active counteranion like salicylate, benzoate or iodide. Indirect photometric (IPD), fluorometric (IFD), or electrochemical (IED) detection is possible by using a counteranion that absorbs, fluoresces, or is electrochemically active. Detection limits for IPD are approximately 0.06 nmole (L-Ala) depending on the AA, mobile phase conditions, and counteranion chromophore for a 3 : 1 signal/noise ratio. - J. Liquid Chromatogr. 16, 597-618 (1993). Univ. Iowa, Dept. Chem., Iowa City, IA 52242 (USA)

6-Methoxy-2-methylsulfonylquinoline-4-carbonyl chloride as a fluorescence derivatization reagent for amines in liquid chromatography. T. Yoshida, Y. Moriyama, K. Nakamura and H. Taniguchi. 6-Methoxy-2-methylsulfonylquinoline-4-carbonyl chloride reacted with primary amines in acetonitrile in the presence of potassium carbonate to give the corresponding fluorescent amides, which could be separated on a TSKgel ODS-80TM reversed-phase column with aqueous 55% v/v acetonitrile as eluent. Pentylamine, hexylamine, heptylamine and octylamine were used to investigate the derivatization conditions. The detection limits (signal-to-noise ratio = 3) of these amines were in the range 0.5-1.0 pmol per 20 ~I injection volume. Alcohols did not give any fluorescent products under these derivatization conditions. - Analyst 118, 2 9 - 3 3 (1993). Meiji Coll. Pharm., Setagaya, Tokyo 154 (J)

Series-coupled capillary columns for the separation of N,(O)-trifluoroacetyl isopropyl derivatives of D,L-aspartic acid and L-hydroxyproline by gas chromatography. Xianwen Lou, Xueliang Liu and Liangmo Zhou. A method for calculating the appropriate length of series-coupled columns was developed. Good results were obtained with this method for the separation of N-trifluoroacetyl (TFAc)-D,L-aspartic acid (Asp) isopropyl ester and N,O-TFAc-L-hydroxyproline (Hpr) isopropyl ester. They give overlapping peaks when a single chiral capillary column is used and can be separated with a cross-linked polycyanoethyl vinyl siloxane-L-Val-tert.-butylamide capillary column coupled in series with either a cross-linked polyethylene glycol 20M capillary column or a wallcoated OV-101 capillary column. D,L-Asp and L-Hpr in real samples were also separated using the series-coupled column systems. - J. Chromatogr. 634, 281 -288 (1993). Inst. Chem. Phys., Acad. Sci., Dalian 116012 (RC) L

Resolution of cyclic imino acid and jl-amino acid enantiomers by derivatization with 2,3,4,6-tetra-O-acetyl-~-D-glucopyranosyl isothiocyanate followed by reversed-phase HPLC analysis. T. Miyazawa, H. Iwanaga, T. Yamada and S. Kuwata. Enantiomeric cyclic imino acids and [3-substituted/3-alanines can be resolved after derivatization with 2,3,4,6-tetra-O-acetyl-[3-D-glucopyranosyl isothiocyanate in aqueous acetonitrile (1 : 1) + 0.4% triethylamine (24, 20°C). The separation was carried out by HPLC on a C18 ODS column with 45--55% methanol + 0.1% acetic acid. The UV absorbance was measured at 250 nm. - Anal. Lett. 26, 367--378 (1993). Dept. Chem., Fac. Sci., Konan Univ., Higashinada-ku, Kobe 658 (J)

Enantiomeric separation of N-protected non-protein amino acid esters by chiral high-performance liquid chromatography. T. Miyazawa, Y. Shindo, T. Yamada and S. Kuwata. The methyl esters of the N-benzyloxycarbonyl derivatives of some non-protein amino acids can be separated by HPLC on a chiral cellulose tris(3,5-dimethylphenylcarbamate)stationary phase using hexane/2-propanol as mobile phase. L-isomers have shorter retention times than Disomers. 13-Amino acids are not so well resolved as s-amino acids. -

] 8] Anal. Lett. 26, 457-473 (1993). Dept. Chem., Fac. Sci., Konan Univ., Higashinada-ku, Kobe 658 (J)

Speciation ofiodo amino acids by high-performance liquid chromatography with inductively coupled plasma mass spectrometric detection. K. Takatera and T. Watanabe. Iodide and 5 iodo amino acids can be specified by HPLC-ICP/MS. HPLC was carried out on a C18-column with 10% or 50% methanol/ 0.1 M (NH4)2 HPO4/0.1% H3PO4 as mobile phase. Using on-line ICP/ MS coupling the absolute detection limits were in a range from 35 to 130 pg as iodine. The relative standard deviation of peak-area measurements was less than 6% for each of the six species. The contents of iodine-containing compounds in an enzymatic digest of bovine thyroglobulin were determined. - Anal. Chem. 65, 759-762 (1993). Inst. Ind. Sci., Univ. Tokyo, Roppongi, Minato-ku, Tokyo 106 (J)

Separation of amino acid homopolymers by capillary gel electrophoresis. V. Dolnik and M.V. Novotny. Capillary electrophoresis with gel-filled capillaries can resolve successfully oligomeric compounds steming from poly(amino acid) preparations. Mixtures of both anionic and cationic nature were adequately resolved. While UV detection at 220 nm was mostly utilized, the polyanions with N-terminal groups can also be tagged with 3-(4carboxybenzoyl)-2-quinolinecarboxaldehydefor a more sensitive detection by a laser-induced fluorescence detetor. The gel composition and the separation conditions were optimized for separations of polyaspartate, polyglutamate and polyarginine. - Anal. Chem. 65, 563-567 (1993). Dept. Chem., Indiana Univ., Bloomington, IN 47405 (USA)

The mechanism of separation of polythiolpeptides and metallopolythiolpeptides by covalent affinity chromatography. A.K.M. Kabzinski. The mechanism of separation of polythiolproteins and metallopolythiolproteins with high density of - S H groups in the peptide chain by covalent affinity chromatography with thiol-disulphide interchange is discussed. Mercury-thionein, cadmium-thionein and apothionein have been used as low molecular weight thiolproteins rich in cysteine residue. The proposed separation mechanism is more complex than those in the literature and can have anionic, cationic or a free radical character depending on the protein, the ligand and the conditions during separations. (145 references). - Chromatographia 35, 439-447 (1993). Biochromatogr. Lab., Dept. Gen. Ecol. Chem., Techn. Univ., Lodz 90924 (PL)

Purpald (4-amino-3-hydrazino-5-mercapto-l,2,4-triazole) as a reagent for post-column derivatization of neutral monosaccharides in high pressure liquid chromatography. M.J. Del Nozal, J.L. Bernal, V. Hernandez, L. Toribio and R. Mendez. Optimum reaction conditions for the post-column detection of 8 neutral monosaccharides with Purpald after HPLC separation have been established. Detection limits from 15 ng for ribose to 80 ng for mannose and rhamnose have been established. - J. Liquid Chromatogr. 16, 1105-1116 (1993). Dept. Anal. Chem., Fac. Sci., Univ. Valladolid, E47005 Valladolid (E)

Determination of carbohydrates by capillary zone electrophoresis with amperometric detection at a copper microelectrode. L.A. Col6n, R. Dadoo and R.N. Zare. Carbohydrates can be analyzed without derivatizsation and/or complexation by capillary zone electrophoresis (CZE) according to their electrophoretic mobilities in strong alkaline solutions (pH ca. 13). Saccharide zones were monitored electrochemically using amperometric detection at a constant potential, 0.6 V (vs. Ag/AgC1), with a cylindrical copper wire electrode (25 gm in diameter). No deterioration ws observed for hundreds of runs. A sample mixture containing 15 different sugars was separated in less than 45 rain with separation efficiencies up to 200000 theoretical plates. The calibration plot was found to be linear over 3 orders of magnitude and the limits of detection for the saccharides studied were in the femtomole range. The method has been applied to

182

1 General analytical methods

the analysis of carbonated soft drinks. - Anal. Chem. 65, 476-481 (1993). Dept. Chem., Univ., Stanford, CA 94305 (USA)

mol/1 (9 ppt). - Anal. Sci. 9, 297-298 (1993). Dept. Mol. Sci. Techn., Kyushu Univ., Kasuga, Fukuoka 816 (J)

Simultaneous GC derivatization and quantification of acids and sugars. M. Morvai-Vitfinyi, I. Moln/tr-Perl, D. Knausz and P. Sass. N-methoxy-N,O-bistrimethylsilyl carbamate (BSMOC) reacts quantitatively with sugars and organic acids in a one-step derivatization. A systematic study has been carried out to optimize the derivatization conditions. Reproducibility data showed that > 0.04 p.g of acids in the presence of < 6 Ixg of sugars can be measured with a relative standard error (R.S.E.) of 6.5% or less. After a simple preparation of fresh apple sample, sugars were converted to their methoximetrimethylsilyl and the acids to their trimethylsilyl derivatives, with BSMOC, simultaneously. Chromatographia 36, 204-206 (1993). Inst. Inorg. Anal. Chem., L. E6tv6s Univ., 1518 Budapest 112 (H)

Gas chromatographic determination of nitrophenols after derivatization with diazomethane. K. Nick and H.F. Seh61er. A GC-PND and GC/MS method is described for the determination of nitrophenols and some of its derivatives as bomoxynil and ioxynile, which are used as herbicides. The compounds were extracted from precipitates with pentane/ether (1 : 1), concentrated by rotary evaporation and methylated by diazomethane. Two capillary columns with different polarity (DB-17 and SE-54) are used which are connected via an Ycolumn with the retention gap. Most of the investigated methylethers could be separated and quantified. The extraction and reaction yields were determined. The resulting recoveries lie between 75 to 100% for the mononitrophenols and in the range of 70% for the methylnitrophenols. The detection limits were about 0.25 gg/1 for most of the substances. - GIT Fachz. Lab. 37, 393-397 (1993). Inst. Sedimentforsch., Univ. Heidelberg, W-6900 Heidelberg (D)

The use of HPLC in the determination of aromatic sulphonates. M.C. Guti~rrez, N. Gago and M. Crespi. HPLC was used to determine the following aromatic sulphonates: toluene sulphonate, xylene sulphonate, naphthalene sulphonate and cumene sulphonate (sodium salts). Detection was carried out at 260 nm wavelength. Different binary mixtures of methanol-water and acetonitrile-water were tested as eluents. The results found with these mixtures obtained on a LiChrospher RP-18 column under isocratic conditions were compared with the PIC technique, using methanol-water and tetramethylammonium phosphate 0,005 M. Better sensibility and reproducibility were obtained by the addition of an ion-pairing reagent to the eluent. - Tenside Surf. Det. 30, 1 5 - 1 7 (1993). Inst. d'Invest. Textil, Univ. Catalunga, E-08222 Terassa High-performance liquid chromatographic analysis of sulfonated aromatics using a ~-cyclodextrin-bonded phase. D.R. Wilder, G.W. Tindall, L.J. Cunningham and J.L. Little. A cyclodextrin-bonded phase can be used with methanol/aqueous ammonium acetate mobile phase for the LC-separation of various sulfonated aromatics. This system is well suited to detection by thermospray LC/MS and it achieves the resolution of positional isomers of sulfonated aromatics. Chromatographic selectivity for these solutes was found to be most significantly influenced by the ionic strength of the mobile phase mixture. - J. Chromatogr. 635, 221 - 2 2 6 (1993). Res. Lab., Eastman Chemical Co., Kingsport, TN 37662 (USA) Simplified and sensitive detection of polyeyclic aromatic hydrocarbons by flash desorption mass spectrometry. Y. Iida, S. Daishima and F. Kanda. Flash desorption and negative ion chemical ionization (NCI) mass spectrometry have been combined to study the detection of polycyclic aromatic hydrocarbons, such as benzo[a]pyrene, at high sensitivity. Such detection below pg orders can be readily accomplished by modifying the ionization chamber to increase the seal, and also be employing rapid heating of the sample loaded filament at a rate of 1000°C/s. This method enabled a several-fold sensitivity increase over both flash desorption with electron ionization and GC/MS with NCI. Furthermore, by setting the sampling points to 20 per second to cope with rapid ionization, a repeatability of within 10% was achieved, thereby allowing quantification utilizing an internal standard. Despite isomeric influences, simultaneous detection of homologs was also possible. Sample size can be reduced to a minimum. The results agree well with those obtained by GC/MS. - Anal. Sci. 9, 245-249 (1993). Fac. Engin., Seikei Univ., Musashino, Tokyo 180 (J) Highly sensitive detection of pyrene by laser muiti-photon ionization on the surface of water. K. Masuda, T. Inoue, To-oru Yasuda, K. Nakashima and T. Ogawa. The laser two-photon ionization techniques described by T. Ogawa, T. Yasuda and H. Kawazumi [Anal. Sci. 8, 81 (1992) and Anal. Chem. 64, 2615 (1992)] is extended to the detection of an aromatic molecule on a water surface. The experimental device is the same described before. It can be shown that the laser multi-photon ionization technique can be used advantageously for detecting photoabsorbing molecules in polar solvents. For pyrene a linear calibration curve over three orders of magnitude has been obtained, the detection limit (S/N = 3) is 4.9 x 10-1

Simultaneous optimization of pH and organic modifier content of the mobile phase for the separation of chlorophenols using a Doehlert design. B. Bourguignon, F. Marcenac, H.R. Keller, P.F. de Aguiar and D.L. Massart. pH and volume fraction of organic modifier was optimized to obtain the complete resolution of a mixture of phenol and thirteen of the nineteen chlorophenol isomers and of a mixture of the three tetrachlorophenols and pentachlorophenol. The effectiveness of the Doehlert design in optimizing both experimental parameters was investigated. A quadratic model was applied. 12 chlorophenols can be separated isocratically in 36% acetonitrile/64% buffer pH 3.9 - J. Chromatogr. 628, 171 - 1 8 9 (1993). Farm. Inst., Vrije Univ, Brussel, B-1090 Jette High-performance liquid chromatographic detection of trace N-nitrosoamines by pre-cohimn derivatization with 4-(2-phthalimidyl)benzoyl chloride. Minghui Zheng, Chengguang Fu and Hongda Xu. Traces of N-nitrosoamines can be determined after denitrosation to secondary amines with a hydrogen bromide-acetic acid mixture, the amines formed then react rapidly with 4-(2-phthalimidyl)benzoyl chloride to give fluorescent amides, which can be separated on an octadecylsilane column with aqueous acetonitrile as eluent. The relative standard deviations (n = 7) at an analyte concentration of 8 x 110- 6 tool 1-1 were less than 5%. The detection limits were in the range 0.4-1.6 pmol per injection. - Analyst 118, 269-271 (1993). Dept. Chem. Engin., Tangshan Univ., Tangshan, Hebei (RC) Sensitive assay system for nitrosoamines utilizing high-performance liquid chromatography with peroxyoxalatc chemiluminescence detection. Chengguang Fu, Hongda Xu and Zhi Wang. HPLC with post-column chemiluminescent detection is a sensitive method for the determination of nitrosamines. The sample was denitrosated with hydrobromic acid-acetic acid to produce the corresponding secondary amines, which were then subjected to reaction with dansyl chloride to form dansyl derivatives. The reaction mixture were separated on a Ca8 reversed-phase column with acetonitrile-water (63.5 : 36.5, v/v) as mobile phase, with 3.0 mmol/1 of imidazole added as a catalyst for chemiluminescence and with the pH adjusted to 6.2 with oxalic acid to give a better separation, followed by detection with a posteolumn chemiluminescence detector using bis(2-nitrophenyl) oxalate and hydrogen peroxide as chemiluminogenic reagents. The sensitivity of this method was more than 120 times greater than that of fluorescence detection and four orders of magnitude greater than that of UV-Vis spectrophotometric detection. The detection limits with this procedure at a signal-to-noise ratio of 4 were between 0.31 and 1.20 pg and the relative standard deviations were between 2.8% and 6.7% for six nitrosamines. The linearity of the calibration graphs and the correlation coefficients were good. - J. Chromatogr. 634, 221-227 (1993). Res. Cent. Phys., Chem. Anal., Hebei Univ., Baoding 071002 (RC) Analysis of anthraquinone sulphonates. Comparison of capillary electrophoresis with high-performance liquid chromatography. S.J. Williams, D.M. Goodall and K.P. Evans.

2.1

] 83

Inorganic geological materials

CE and HPLC are compared for the analytical separation of anthraquinone-l-sulphonate and its related impurities anthraquinone-2sulphonate, anthraquinone-l,8-disulphonate and anthraquinone-l,5disulphonate. Optimum conditions for CE use a borate solution (50 mM NaH2BO3 and 8 mM H3BO3) as background electrolyte at pH 10.0 and for HPLC acetonitrile-water (60:40) containing 0.8 % (w/v) cetyltrimethylammonium bromide as eluent. Analysis times of 17 min are comparable. Quantitative aspects including CE and HPLC efficiency, linearity, precision and limits of detection (LOD) are compared. For anthraquinone-l-suphonate the CE concentration LOD is 0.7 gg ml-I and the HPLC LOD is 6 ng ml-1: mass LODs are 3 and 60 pg, respectively. Assay precision is 2% R.S.D. in peak area by CE using instruments from several manufactures. This is improved to better than 0.5% R.S.D. in relative peak areas when a co-injected analyte is used as an internal standard. - J. Chromatogr. 629, 3 7 9 - 384 (1993). Chem. Dept., Univ., York YO1 5DD (GB)

Enantiomerie separation of close analogs to naturally occuring 1,4benzoxazin-3-ones by liquid chromatography using/I-cyclodextrin-modifled stationary phase. T. Lippmann, H. Hartenstein and D. Sicker. A liquid chromatographic procedure on a 5 gm LiChroCART column using chemically bonded [3-cyclodextrin (ChiraDex) as chiral selector was developed for the enantiomeric separation of four 2H-I,4benzoxazin-3(4H)-ones which are close analogs of the cyclic hydroxamic acids 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (DIBOA) and 2,4dihydroxy-7-methoxy-2H-1,4-benzoxazin-3 (4H)-one (DIMBOA) naturally occuring in Gramineae species. The separation of DIBOA 5 and DIMBOA 6 is not possible due to the rapid oxo-cyclo tantomerization of these compounds. Methanol/water mixtures were used as mobile phases and detection was carried out at 254 nm. - Chromatographia 35, 302-304 (1993). Inst. Org. Chem., Univ., O-7010 Leipzig (D) Continuous-flow fast atom bombardment liquid chromatography/mass spectrometry of carotenoids. R.B. van Breemen, H.H. Schmitz and S.J. Schwartz. Carotenoid molecular ions were identified using continuous FAB/LC/ MS with coaxial flow addition of the FAB matrix, 3-nitrobenzyl alcohol. The limit of detection of this LC/MS technique was approximately 5 ng for lutein and 15 ng for or-carotene, compared to 40 and 70 ng for lutein and s-carotene, respectively, using a photodiode array detector. Structurally significant fragment ions specifically identifying the isomeric carotenoids, m-carotene, [~-carotene, and lycopene, were obtained during LC/MS using the MS/MS technique of B/E linked scanning with collisional activation. I~inally, continuous-flow FAB LC/MS with coaxial-flow matrix addition was used to identify carotenoids present in a tomato extract. - Anal. Chem. 65, 965-969 (1993). Dept. Chem., Univ., Raleigh, NC-27695-8204 (USA) Flow-injection sample preparation for orgauotin speciation analysis of water by capillary gas chromatography/microwave-induced plasma atomic emission spectrometry. J. Szpunar-Lobiflska, M. Ceulemans, R. Lobiflski and F.C. Adams. The derivatized species are eluted with 250 gl of methanol, separated by gas chromatography and detected with a microwave-induced plasma atomic emission detector. Aliquots of 25 gl of the eluate are introduced onto a capillary column using the cool injection technique. The solvent is vented off in the liner before the temperature of the latter is raised to release the analytes. A 1 0 - 5 0 ml water sample is sufficient for the analysis and a detection limit of 0.1 ng 1-~ can be obtained. The developed procedure was applied to the determination of organotin compounds in a number of river water samples which were analysed in parallel using a manual liquid-liquid extraction procedure. The results agreed within 10 - 15% for concentration of a few ng 1- 1. A comprehensive optimization study of the sorption of mono-, di- and tributyl- and phenyltin compounds using C18 packed microcolumns and extraction discs is carried out followed by in situ heterophase derivatization of ionic species using NaBEt4. - Anal. Chim. Acta 278, 99--113 (1993). Dept. Chem., Univ. Antwerp (ULA), B-2610 Wilrijk Determination of colloidal electrolytes: conductimetrie titration of hydroxyzine hydrochloride with ammonium molybdate. R. Mikulski and B. Dembifiski.

A rapid and accurate conductometric titration method is proposed for the determination of hydroxyzine hydrochloride. A solution containing 1 - 3 0 mg of hydroxyzine hydrochloride can be titrated conductimetrically with ammonium molybdate. The proposed method was checked by the determination of hydroxyzine hydrochloride in a Hydroyzinum preparation. - Anal. Chim. Acta 272, 233-235 (1993). Inst. Chem., Univ., PL-87100 Torufi

Chiral resolution of enantiomers of asymmetric cobaltacarboranes with a monoatomic bridge between ligands by liquid chromatography on a /~cyclodextrin column. J. Ple~ek, B. Grfiner, T. Van~k and H. VotavovA. [~-Cyclodextrin CSPs are efficient for the HPLC resolution of thirteen enantiomeric pairs of racemates of the type 6,6'-p-R-E-(1,7-C2BgH10)22-Co with oxygen, sulphur and nitrogen bridges (E) and with a variety of R substituents differing in size and electronic properties along with structural factors influencing the capacity factors, selectivity and resolution of individual compounds. A semipreparative method for chiral separations of these racemates is described and circular dichroism (CD) spectra of several pure enantiomers are presented. The CD spectra indicate the same absolute configurations of all enantiomers eluted first or last independent of the nature of the bridging atom and the size of the bridge substituting group R. - J. Chromatogr. 633, 73 - 80 (1993). Inst. Inorg. Chem., Acad. Sci., 25068 t~e~ near Prague (Czech. Rep.) Optimization of a flame photometric detector for supercritical fluid chromatography of organotin compounds. J. Dachs and J.M. Bayona. The suitability of single flame FPD coupled to capillary supercritical fluid chromatography (cSFC) is demonstrated for trialkyltin chlorides. Detection variables (temperature, hydrogen and air flow-rates) were optimized by a combination of factorial experimental design and simplex. Furthermore, the position of the restrictor in the flame and injection volumes were also considered. Optimum sensitivity was achieved using high hydrogen-air ratios (1.8). Using the optimum conditions, baseline was stable during pressure programming. The detection limit of tributyltin chloride (S/N = 3) was around 40 pg (as tin). Reproducibility was high (R.S.D. = 3.8%, n = 5 ) and dynamic range was measured over two orders of magnitude. Furthermore, dibutyl-, diphenyl- and triphenyltin chlorides were also successfully eluted for the first time using linear density programming (carbon dioxide, 50°C). - J. Chromatogr. 636, 277-283 (1993). Environ. Chem. Dept., C.I.D.-C.S.I.C., 08034Barcelona (E) A comparative study of gas chromatography with atomic absorption and atomic emission detection for the speciation analysis of organotin. W. Dirkx, R. Lobiflski and F.C. Adams. Megabore column gas chromatography quartz furnace atomic absorption spectrometry (MCGC-QFAAS) and MCGC graphite furnace AAS (MCGC-GFAAS) were used for the determination of pentylated organotin species and compared with existing techniques, like packed column (PC) GC-AAS and capillary columns (CC) GC-atomic emission spectrometry (AES). Particular attention was given to the design of the interface between a GC column and the detector cell (GF or QF) as well as optimization of the operational variables of the interface and detector. The accuracy of the developed techniques is discussed on the basis of an intermethod comparison analysis of 15 water samples. - Anal. Sci. 9, 273-278 (1993). Dept. Chem., Univ. Antwerp (U.I.A.), 2610 Wilrijk

(S)

2

PARTICULAR MATRICES AND FIELDS OF APPLICATION

2.1

Inorganic geological materials

Optimization of neutron activation analysis of rock samples. N.A. Shubina and G.M. Kolesov. Factors as irradiation and mass of samples, time of cooling and measuring time are optimized for neutron activation analysis of

184 ultrabasic rock samples using thermal and epithermal reactor neutrons. The method enables to improve the limits of detection of elements and can be used for prior estimation of conditions of the analysis of samples of any composition. - Chem. Analit. 37, 699-709 (1992). Vernadsky Inst. Geochem., Anal. Chem. Russian, Acad. Sci., 117975 Moscow, V334 (Russia)

Cyclodextrin stationary phases for the gas-solid chromatographic separation of inorganic gases. G i . Reid, III, W.T. Wall and D.W. Armstrong. Cyclodextrins bonded to silica-gel support and used as a GSC stationary phase is useful for separating a wide variety of gases. Evaluation of different cyclodextrin columns and the analogous silica gel support column with inorganic gas standards is reported. Separation selectivities and efficiencies differ between silica gel and the cyclodextrin phases. Capacity factors and chromatograms are presented for these gas-solid chromatographic stationary phases. The native cyclodextrin stationary phases appear to retain gases via at least two different retention mechanisms. - J. Chromatogr. 633, 143-149 (1993). Dept. Chem., Univ., Rolla, MO 65401 (USA) Monitoring of vapor-phase nitro compounds using 226-nm radiation: Fragmentation with subsequent NO resonance-enhanced multiphoton ionization detection. G.W. Lemire, J.B. Simeonsson and R.C. Sausa. The sensitive detection of nitro compound vapors is achieved with a one-laser photofragmentation/fragment detection technique. A laser tuned to 226 nm is used as well for the photolysis of the target molecule as for the detection of the characteristic NO fragment. The analytical utility of this technique is demonstrated on a number of compounds, including dimethylnitramine, nitromethane, nitrobenzene, trinitrotoluene (TNT), and 1,3,5-trinitrohexahydro-l,3,5-triazine (RDX), employing molecular beam sampling with time-of-flightmass spectrometric analysis of the jet-cooled analyte seeded in an atmosphere of buffer gas. Limits of detection of 8 and 24 parts per billion (ppb) are obtained for RDX and TNT, respectively, using only ~ 100 gJ/pulse of laser energy. -- Anal. Chem. 65, 529 - 533 (1993). US Army Res. Lab., AMSRLWT-PC, Aberdeen Proving Ground, MD-21005-5066 (USA) Improvements in preconcentration methods for determining trace impurities in ultra-pure gases by gas chromatography. L.X. Wu and H.N. He. Three concentration methods for eliminating blank errors are investigated. These are, the differential volume method by concentrating at the same flow-rate but different times (DVMSF), the differential time method by concentrating the same volumes at different flow-rates (DTMSV) and the differential volume method by concentrating for the same times but different flow-rates (DVMST). DVMST is proposed as the best method for its ability to eliminate all blank errors described. The methods are used to determine trace amounts of Ar + 02 and N2 in ultra-pure hydrogen. Calculations demonstrate that the methods can effectively improve analytical accuracy. - Chromatographia 35, 339 343 (1993). Shanghai Inst. Metallurg., Acad. Sci. China, Shanghai 200050 (RC) Luminescent dicyanoplatinum(II) complexes as sensors for the optical measurement of oxygen concentrations. W.W.S. Lee, K.Y. Wong and X.M. Li. [Pt(L)(CN)2] (L = 4,7-diphenyl-l,10-phenanthroline or 4,4'-di-tertbutyl-2,2'-bipyridine) immobilized in silicone rubber are stable and sensitive materials for the measurement of gas phase oxygen concentrations. The polymer films containing the platinum complex are very stable, and no photochemical degradation was observed when they were subjected to step changes in the oxygen concentration. The films are not sensitive to alkyl halides such as chloroform and dichloromethane. Sulfur dioxide, on the other hand, is a fairly severe interferent. - Anal. Chem. 65, 255 258 (1993). Dept. Appl. Biol., Chem. Technol., Hong Kong Polytechnic, Hunghom, Kowloon (HK) Determination of carbon monoxide and carbon dioxide concentrations at temperatures between 295 and 1250 K using Fourier transform infrared absorption spectroscopy. P.J. Medvecz and K.M. Nichols.

2

Particular matrices and fields of appiication

Fourier transform infrared absorption spectroscopy has been used for the determination of CO and CO2 gas concentrations in a hightemperature cell. The temperature of the gas cell was varied between 295 and 1250 K, while the pressure was maintained at atmospheric. 123 absorption spectra were recorded in the gas cell. The absorption lines used for the concentration analysis consisted of 22 P-branch CO vibrational-rotational lines from the fundamental absorption band, and 19 R-branch CO2 vibrational-rotational lines from the va fundamental absorption band. The peak heights used were first numerically corrected for photometric errors. The corrected peak heights were assumed to follow the Bouguer-Lambert law at a constant furnace temperature. The experimentally obtained line strengths were used to determine the gas concentrations of all 123 spectra. Comparison of the NDIR measured gas concentrations with the calculated concentrations from absorption spectra yielded an average accuracy of 3.6% for the CO spectra and 4.9% for the CO2 spectra. - Appl. Spectrosc. 46, 1887-1994 (1992). Inst. Paper Sci. Technol., Atlanta, GA 30318 (USA)

Measurement of sulfur dioxide with the differential optical absorption technique combined with Fourier transformation. L. Axelsson and A. Lauber. Fourier transformation, applied on a differential absorption spectrum, can be used to detect a very weak absorption spectrum of SO2 at 2 9 0 310 nm. Measurements have been made with a pathlength of two meters and a measuring time of one minute. Sulfur dioxide levels of less than 0.1 ppm (volume) were assessed with a measurement uncertainty of _+0.03 ppm (volume). This method also shows good robustness against displacements in the wavelength range of the incoming absorption spectrum. - Appl. Spectrosc. 46, 1832-1836 (1992). Dept. Phys., Measurem. Inst. Technol., Univ., S-58183 LinkSping Monitoring of sulfur dioxide using a piezoelectric crystal based controller. F. Benmakroha, T. Boudjerda, R. Boufenar, H. Allag, F. Djerboua and J.J. McCallum. Ethylenedinitrilotetraethanol, triethanolamine and N,N,N',N'tetrakis(2-hydroxypropyl)ethylenediamine coated piezoelectric crystals were tested as sensing element for sulfur dioxide in the environment. The device is configured as a detector/monitor giving an alarm rather than a control function. Additionally, a transmitter was added to allow remote monitoring. Good results were obtained at ambient and higher than ambient temperatures. NO2 can interfere. - Analyst 118, 4 0 1 406 (1993). Lab. Governm. Chemist, Teddington, Middlesex, TWl 1 0LY (GB) Determination of aluminium in high purity water by ion-exchanger phase spectrofluorometry combined with flow analysis. S. Matsuoka, K. Yoshimura and A. Tateda. Ion-exchanger phase spectrofluorometry combined with flow analysis, has been applied to the determination of aluminium in high purity water. The complex formed between aluminium and morin in the flow system was concentrated on a SP-Sephadex C-25, a dextran cation-exchanger, packed in a flow-through fused-silica micro cell. The increase in fluorescence intensity caused by the on-line concentration of the complex in the gel was continuously measured with a spectrofluorometer. The detection limit was 15 ng dm -3. Aluminium in 5 sample solutions (4 cm 3) could be determined within 1 h. - Mere. Fac. Sci., Kyushu Univ., Ser. C, 18, 169-178 (1992). Coll. General Educ., Kyushu Univ., Chuo-ku, Fukuoka 8J0 (J) Determination of lanthanum by flame atomic emission spectrometry in rare earth concentrates. M. Kumar and P.K. Srivastava. Ammonium chloride has been used in the determination of lanthanum to eliminate the depressive effect caused by different interferents. Lanthanum is determined by flame atomic emission spectrometry using a dinitrogen oxide-acetylene flame and a baseline method for background correction, by scanning the atomic emission spectra in the region 441.2442.2 nm. The concentration of lanthanum is calculated from the peak height of the LaO band at 441.8 nm. The relative standard deviations vary from 1.1 to 2.8%. The proposed method has been applied to synthetic mixtures and rare earth concentrates. -- Analyst 118, 193-

2.1

Inorganic geological materials

195 (1993). Chem. Lab., At. Min. Div., Dept. At. Energy, West BlockVII, R.K. Puram, New Delhi-110066 (IND)

Determination of gold and palladium in manganese and nickel compounds by atomic absorption spectrometry after separation by use of amberlite XAD-7 resin. L. Elci. Traces of Au and Pd can be concentrated from manganese, nickel and their compounds at a small column filled with Amberlite XAD-7 resin. Base matrix elements are washed offwith 0.5 M HC1 + 0.01 M KSCN and the elements are eluted with acetone and consequently determined by FAAS. The relative standard deviations (N= 10) were found to be lower than 5% ; the detection limit (3s, N - 20) for Au and Pd in metal samples is 0.07 pg/g. - Anal. Lett. 26, 1025-1036 (1993). Dept. Chem., Fac. Art, Sci., Erciyes Univ., 38039 Kayseri (TR) Fractional determination of crystalline and non-crystalline copper(I) oxide in metallic copper. K. Tsuruoka and Y. Kikuta. Crystalline copper(I) oxide and non-crystalline copper(I) oxide in copper powder, in which no copper(II) oxide was included, were determined by a combination of wet chemical and XRD methods. The XRD method gave the concentration of crystalline copper(I) oxide and allowed the non-crystalline copper(I) to be subtracted from the total copper(I) oxide concentration found by the wet chemical method. This combination method is found capable to obtain the concentration of noncrystalline copper(I) oxide because of good reproducibility of both wet chemical and XRD methods. Bunseki Kagaku 42, T13 - T 1 7 (1993); (Orig. Jap.) Anal. Phys. Prop. Cent., Showa Denko K.K., Ohta-ku, Tokyo 146 (J) Ion chromatography in the analysis of high purity refractory metals. A. Seubert. The advantages of ion chromatography in comparison to the commonly used methods like AAS lie in the high mass sensitivity and the possibilities of preconcentration. To determine Mo and W in refractory metals in the ng/g range a sensitive combined technique is proposed which is called the IC-SMT-IC method. For this method a commercially available isocratic HPLC apparature is modified by an additional 6-port valve. Using tartaric acid as eluent and Nucleosil SA as stationary phase most of the elements used in microelectronics can be separated and detected in one run. For the s-emitter U and Th a new elution system based on citric acid is proposed, which allows the determination of both elements nearly without any interference. - GIT Fachz. Lab. 38, 5 - 12 (1993). Inst. Anorg. Chem., Univ., W-3000 Hannover (D) Direct determination of copper in iron alloys and aluminium alloys by ultraviolet third-derivative spectrophotometry. Wang Naixing. The third-derivative spectra of copper with cyanide both eliminate the interference from other metals and improves the sensitivity. Beer's law is obeyed for 0.64-3.2 gg/mi of copper. The relative standard deviation for 7 determinations 1.5 gg/ml of copper was 0.78%. The detection limit (S/N = 2) was 0.15 pg/ml. The suggested method has been applied successfully to the analysis of some iron alloys and aluminium alloys without any separation. - Anal. Lett. 26, 513 -- 522 (1993). Dept. Chem., Shandong Univ., Jinan, 250100 (RC) Determination of ultratrace uranium and thorium in high purity aluminium by NAA. Y. Okada and S. Hirai. Ultratrace amounts of uranium and thorium in high purity aluminium were determined by RNAA. The aluminium plate samples (ca. 1 ~ 10 g) were irradiated by thermal neutron flux of 4 x 1012 n cm- 2 s- 1 for 5 ~ 10 h at Musashi Institute of Technology Research Reactor (MITRR). After several days the irradiated samples were dissolved in 9 M HC1 for anion exchange chromatography, a39Np and 233Pa adsorbed on the anion exchange resin from 9 M HC1 were selectively eluted with 9 M HC1-5 M HF solution. By-the addition of LaC13 solution to this eluate, 239Np and 233Pa coprecipitated LaF3. y-Rays from the coprecipitate on a filter paper were measured for determination of uranium and thorium. Several ppt levels of uranium and thorium can be determined. The analytical results obtained by RNAA indicated excellent agreement with the INAA results. - Bunseki Kagaku 42, 249--254 (1993). (Orig. Jap.) Atom.

]85 Energy Res. Lab., Musashi Inst. Technol., Kawasaki-shi, Kanagawa 215

(J) Determination of trace silicon in high purity iron by molybdosilicic acid blue spectrophotometry following fluoride separation. M. Kiyokawa, H. Yamaguchi and R. Hasegawa. A modified fluoride separation-molybdosilicic acid blue spectrophotometry using masking reagent of iron was applied to determine trace silicon in high purity iron samples. Decompose 1.0 g of sample with a solution of sulfuric acid 2 ml and nitric acid 0.5 ml. After cooling the solution, add phosphoric acid 5 ml as masking reagent and hydrofluoric acid (1%) 0.5 ml and then sulfuric acid 20 ml, to yield volatile silicon tetrafluoride. Transfer the fluoride compietely into a boric acid solution by purging it with nitrogen. Then add hydrochloric acid and ammonium moiybdate to form molybdosilicate. After adding oxalic acid and ascorbic acid, measure the light absorbance of the solution at 810 nm. By this method, ppm level silicon in commercial high purity irons (4N and 5N) and sub-ppm level silicon in JSS standard high purity iron sample were successfully determined. Recovery (n = 10) was 96% for 10 gg of silicon and the detection limit given by 3c~ of blank value was 0.06 ppm. - Bunseki Kagaku 42, 212-222 (1993); (Orig. Jap.) Nat. Res. Inst. Metals, Meguro-ku, Tokyo 153 (J) Quantitative X-ray fluorescence analysis of Fe-Al and Cu-Fe binary alloys using selective excitation. W. Ladisich and P. Wobrauschek. Three excitation modes for Fe-A1 binary alloys were compared using an energy-dispersive spectrometer system. The method of selective excitation is especially suited for types of samples where the line with minor intensity also has the lower energy. Fe-A1 alloys can be analysed by selective excitation with an extrapolated lower limit of detection for A1 in Fe down to 0.04 wt.% (measuring time 1000 s) using an energydispersive spectrometer system. The scattered primary radiation was of great importance for exciting the higher Z element in the sample. Extrapolated lower limits of detection for Fe in Cu are in the pg g (ppm) range (anode Mo, secondary target Ni). The calculated I(A1)/ I(Fe) ratio as a function of the sample composition is in good agreement with experimental data. Using this approach, a single standard is sufficient for quantitative analysis. - X-Ray Spectrom. 22, 151-155 (1993). Atominst. Osterr. Univ., A-1020 Vienna (A) Simultaneous determination of arsenic, bismuth and antimony in steels and nickel alloys by inductively coupled plasma atomic emission spectrometry with hydride generation. E.A. Ozaki and E. de Oliveira. The determination of As, Bi and Sb in low alloy steels, stainless steels, and Ni alloys by hydride generation can be achieved by adjusting both the acid and the Fe(III) concentrations to significantly reduce the Ni interference. A well defined relation between acid and Fe(III) concentration has to be maintained. The accuracy of the proposed procedure was in agreement with the reported reference values for As, Bi and Sb in the steels and the certified values for the Ni alloy for CRMs. - J. Anal. At. Spectrom. 8, 367-370 (199:3). Univ., Silo Paulo, Inst. Quire., CP 20780, CEP01498, SP (BR) Ion-chromatographic separation and determination of some metal ions in stainless steels by pre-column chelation with 4-(2-thiazolylazo)resorcinol (TAR). R. Saraswati and T.H. Rao. By using TAR as pre-column chelating agent, metal ions in stainless steel can be separated and determined using an ion chromatograph with a C18 column. The requirements for sample preparation, and the conditions for pre-column chelation reaction are discussed. The pH of the chelating medium and the eluent, the concentration of TAR and the composition of the eluent were investigated. The detection limits achieved were 3.2, 2.5, 0.6, 0.8, 1.2, 2.9, 3.0, 4.2, and 4.0 ng for V, Zr, Cu, Ni, Mn, Co, Pb, Nb and Ta respectively. The results obtained by IC methods compare well with those of GFAAS methods and the certified values of SRM. - J. Liquid Chromatogr. 16, 1601-1614 (1993). Instrum. Anal. Group, Def. Metall. Res. Lab., Kanchanbagh P.O., Hyderabad-500258 (IND) Determination of trace impurities in tantalum oxide and niobium oxide by laser ablation inductively coupled plasma mass spectrometry. S.T.G. Anderson, R.V.D. Robert and H.N. Farrer.

186 Rapid methods requiring only minimal sample preparation have been developed for the determination of trace impurities in Ta205 and NbzO5 by ICP-MS. The ground samples were pressed into pellets. The limits of detection are less than I pg g - 1 for most elements, and relative standard deviations are of the order of 0.15. - J. Anal. At. Spectrom. 7, 11951199 (1992). Anal. Sci. Div., Mintek, Randburg 2125 (ZA) Determination of acid soluble and insoluble boron in nickel-base heat resistant alloys by curcumin spectrophotometry. Y. Toida and K. Watanabe. Procedures for the curcumin photometric determination of both acid soluble and insoluble boron in nickel base heat resistant alloys were studied. The sample was dissolved in sulfuric acid. Insoluble boron could be quantitatively recovered. Addition of glycerine was proved to be effective to prevent volatilization loss of boron during evaporation of sample solutions. The procedure was applied to nickel base alloys. The sum of soluble and insoluble boron obtained by this method was in good agreement with total boron determined separately. - Bunseki Kagaku 42, T43-T46 (1993); (Orig. Jap.) Anal. Chem. Lab., Dept. Chem., Japan Atom. Energy Res. Inst., Tokai-mura, Ibaraki 319-11 (J) Solvent extraction and chemiluminescence determination of gold in silver ahoy with luminol in reverse micelles. Imdadullah, T. Fujiwara and T. Kumamaru. Gold can be determined in aqueous solutions by the direct combination of solvent extraction with luminol chemiluminescence (CL) in a reversed micellar system of cetyltrimethylammonium chloride-water (buffered with sodium carbonate)- 6:5 (v/v) chloroform-cyclohexane. The interference behavior of 15 metals on the reference gold CL signals was evaluated. Separation of analyte from interferents by extraction with tri-n-octylphosphine oxide in chloroform resulted in reduced or no interference. The present method was applied to the determination of gold in industrial samples of silver-based alloy. - Anal. Chem. 65,421 424 (1993). Dept. Chem., Fac. Sci., Univ., Higashi-Hiroshima 724 (J) Microanalysis of bismuth indium selenide thermoelectronic materials by Xray fluorescence spectrometry with reference assays of indium. S. Kotrl~, J. Sr/tmkovfi, R. Chadima and J. Cerm/tk. Statistical analysis of numerous experimental data is used to assess the applicability of XRF measurements on a small area of a natural crystal face. The problems o f X R F calibration based on an accurate chemical determination of indium are also discussed in detail. A precise determination of indium (within the range 1 - 8 % m/m) in Bi2-xlnxSea single crystals was based on the calibration of the net intensity of the In K~1,2 line with the use of the results of extraction-photometric analysis after decomposition of the crystal chips exposed to X-rays. In acetate buffer medium (pH ~ 4.0) and with an adequate excess of quinolin-8ol and thiosulfate (masking of bismuth), the tris(quinolin-8olato)indium(III) chelate was completely transferred into chloroform. The absorbance of the chloroform extract was measured at 400 nm against a blank extract. For calibration of the X-ray spectrometer a computer program was written. - Analyst 118, 7 9 - 8 3 (1993). Dept. Anal. Chem., Univ. Chem. Technol., 53210 Pardubice (CS) Determination of ultra-trace copper on silicon wafer by neutron activation analysis. H. Yonezawa, K. Shikano and T. Shigematsu. An analytical method for determining ultra-trace Cu on silicon wafer by NAA was studied. To estimate the amount of contamination received from packing materials during irradiation in a nuclear reactor, surface metal concentrations of 4 kinds of fluoride polymer film and 2 kinds of polyethylene film were determined by NAA. Cu contamination from this film is below 101° atoms cm -2. The amount copper on a silicon wafer during irradiation is below 6 x 109 atoms cm-2. The wafer, which has been spin coated with a Cu solution of 0.1 to 40 ppm, was also analyzed. A good linearity of solution concentration and surface concentration of Cu was obtained. The intentionally contaminated wafer of a desired concentration can be produced. The detection limits of Cu is 4 × 109 atoms cm -2 by instrumental analysis with a well Ge detector and is improved by utilizing chemical separation and a low back-ground gas flow counter. - Bunseki Kagaku 42, 229-233 (1993); (Orig. Jap.) NTT Interdisciplin. Res. Lab., Tokai, Ibaraki 319-11 (J)

2

Particular matrices and fields of application

Spectrophotometric analysis of average valence of bismuth and copper in superconductor by use of small amounts of sample. K. Watanabe, N. Takamoto and K. Fueki. The determination of the average valence of Bi and Cu in the superconductor Bi-Sr-Ca-Cu-O by use of small amounts of sample was investigated. Bi(V) reacts with Mn(II) to form permanganate in nitric acid solution. Bi(V) could be determined in the presence of large amount of Mn(II) ion. The absorbance of the sample solution was measured at 525 nm in order to calculate the amount of Bi(V). Then, the total amount of Bi was determined to obtain the average valence of Bi by spectrophotometry with KI. For this purpose to the sample solution was added 0.1% ascorbic acid to reduce Mn(VII) and Cu(II) and KI and 0.1% Zephiramine. The Zeph +BiI4- complex was extracted with chloroform and measured at 492 rim. The mixture of Cu(II) and Cu(III) was determined by iodometry. The liberated I2 corresponding to the sum of the valence change of copper was extracted with chloroform as Zeph +I3 -. The absorbance due to both Bi(V) and Bi(III) were corrected from the calibration curves constructed previously. The total amount of copper in the sample was determined with bathocuproine by using the other parts of the sample remained as a solution. - Bunseki Kagaku 42, 3 3 - 3 8 (1993); (Orig. Jap.) Fac. Sci. Technol., Sci. Univ. Tokyo, Noda-shi, Chiba 278 (J) Substoichiometric ion-pair extraction and determination of barium(II) with macrocyclic crown ether and cryptand. T. Fukaya, H. Imura and N. Suzuki. The extraction of Ba(II) with 18-crown-6 and cryptand-2.2.2 into benzene, 1,2-dichloroethane and nitrobenzene was studied by using picrate as counterion at an ionic strength of 0.10 M (HC1-LiC1). Ba(II) is substoichiometrically extracted into 1,2-dichloroethane or 1,2dichloroethane-nitrobenzene(1 + 1) with (0.5-1) x 10-4 M a 8-crown-6 or cryptand-2.2.2 in the presence of ( 1 - 2 ) x 10 -2 M picrate at pH 4 10 or 7 - 1 1 , respectively. The 18-crown-6 system was superior to the cryptand-2.2.2 system in selectivity toward other alkaline earth and alkali metals. The substoichiometric process combined with isotope dilution was successfully applied to the accurate determination of barium in a Y-Ba-Cu-O superconducting ceramic. - Anal. Chim. Acta 272, 279-284 (1993). Dept. Chem., Fac. Sci., Tohoku Univ., Sendai 980 (J) Partial least squares techniques in the energy-dispersive X-ray fluorescence (ED-XRF) determination of sulfur-graphite mixtures. J. Swerts, P. van Espen and P. Geladi. Partial least square (PLS) methods can be used in combination with ED-XRF to quantitate sulfur in a graphite matrix. Because of interferences and abnormal scattering of the excitation radiation (diffraction effects), spectrum evaluation using least squares fitting failed. The PLS method on the other hand is able to predict the S concentrations with an accuracy better than 5% in the concentration range of 2 - 6 0 % . The various artifacts observed in the spectra can be explained with the PLS model. - Anal. Chem. 65, 1181-1185 (1993). Dept. Chem., Micro, Trace Anal. Centre, Univ. Antwerp, 2610 Wilrijk (B) Rapid determination of strontium-90 in highly radioactive solutions of nuclear fuel reprocessing plant. Y. Kuno, S. Sato, E. Ohno and J. Masui. 9°Sr can be determined in highly radioactive solutions from nuclear fuel processing plants by precipitating the majority of fission products (FPs) including 90y in an alkaline medium, leaving 9°St in the supernatant in the presence of inactive strontium as the hold-back carrier. 90y freshly grown-in from the 9°Sr is measured by utilizing a Cerenkov radiation counting technique with stainless steel shielding 0.2 mm thick that cuts off any low energy 13-particles, after strontium is recovered as a carbonate precipitate from the supernatant. The concentration of 9°Sr is calculated from the 90y detected and its grow-in time. The nuclides potentially interfering with this method, l°tRu, 134Cs, 137Cs, 14~Ce, 144Pr, 147Pm, lS4Eu, 123Sn and 125Sb, are quantitatively removed by coprecipitation with iron(II) hydroxide during the alkaline precipitation stage. The relative standard deviation (n = 5) is better than 5%. The time required for one determination is less than 3 h. - Anal. Sci. 9, 195 - 198 (1993). Power Reactor, Nucl. Fuel Develop. Corp. (PNC), Muramatsu, Tokaimura, I baraki 319-11 (J)

2.1

Inorganic geological materials

Application of laser ablation ICP-MS to elemental analysis of glasses. J.L. Imbert and P. Telouk. A technique involving the coupling of laser ablation and inductively coupled plasma mass spectrometer has been used for semi-quantitative analysis of glasses without sample dissolution. The characteristic features of this technique is low detection limit and accuracy between a few % up to 20%. An NIST glass standard (SRM 612) was dissolved and then analysed by ICP-MS in semi-quantitative mode. The results were in close agreement with the certified values for elements such as Mn, Sr, Y, Ti. Mikrochim. Acta 110, 151-160 (1993), C.N.R.S. Serv. Centr. d'Anal., chemin du canal BP 22, F-69390 Vernaison (F) Determination of iron, cobalt, nickel and copper in a zirconium-based glass by electrothermal atomic absorption spectrometry. J. Jaganathan, K.J. Ewing and I. Aggarwal. By dissolving a zirconium-based fluoride glass in a solution of zirconium oxychloride, ZrOC12' 8H20, the direct determination of Fe, Co, Ni and Cu was achieved by ET-AAS. The accuracy of results obtained from solution analysis was confirmed using a preconcentration method carried out independently. The average precision of measurements (relative standard deviation) for all the elements was < i 0 % and the methodological detection limits for Fe, Co, Ni and Cu, based on the preconcentration technique, were 0.05, 0.04, 0.1 and 0.04 ng g - 1, respectively. - J. Anal. At. Spectrom. 7, 1287-1294 (1992). GEO Centers, Inc., Fort Washington, MD 20744 (USA) Laser ablation ion trap mass spectrometry (LAITMS): Atomic and molecular mass spectrometry of metal, ceramic and polymer samples. Plenary Lecture. C.G. Gill and M.W. Blades. Optimum conditions for the collection of spectra using LAITMS have been determined for metallic, ceramic and polymeric samples. Advantages and disadvantages using LAITMS for direct solid mass spectrometry are discussed. The effects of sample surface preparation and laser flux were investigated for stainless-steel samples. - J. Anal. At. Spectrom. 8, 261--267 (i993). Dept. Chem., Univ., Vancouver, British Columbia, V6T IZ1 (CDN) Measurement of trace elements in ceramic and quartz by laser ablation microwave-induced plasma atomic emission spectrometry (LA-MIP-AES). Plenary Lecture. A. Ciocan, L. Hiddemann, J. Uebbing and K. Niemax. The application of LA-MIP-AES to the determination of trace elements in a high-temperature superconducting ceramic (YBazCu307) and high-purity quartz is reported. The emission spectra of Mg, A1, Si and Fe were measured by time-gated detection, normalized by internal standardization and calibrated with relevant spectra of standard reference samples. The high sensitivity of this direct analytical method was demonstrated by the determination of Na at the ng/g level in high-purity quartz. - J. Anal. At. Spectrom. 8, 273 - 2 7 8 (1993). Inst. Spektrochem., Angew. Spektrosk., W-4600 Dortmund 1 (D) Reduction of secondary ion mass spectrometry matrix effect for high dose chromium and cobalt implanted silicon. C. Tian, G. Stingeder and H. Bubert. The dependence of S2Cr+ ion yield on Cr concentration in the Si matrix is investigated by recording energy spectra of sputtered 52Cr+ ions. The matrix effect influences mainly low-energy ions. It can be eliminated within the analytical accuracy if the secondary ion energy is higher than 60-100 eV. Although sensitivity is lost by ~ 2 orders of magnitude, a detection limit of 1 ppm atomic (10 -6 atomic fraction) and detailed depth profiles are obtained for such samples. An energyfiltering technique can be used to effectively reduce or eliminate this matrix effect and quantitative depth profiles of metal silicide specimens with a high dynamic range can be obtained by SIMS. - Anal. Chem. 65, 1035-1037 (1993). Inst. Anal. Chem., Teehn. Univ. Wien, Getreidemarkt 9/151, A-1060 Wien (A) Determination of silicic acid in highly purified water by improved gel-phase absorptiometry. U. Hase and K. Yoshimura. Improvements in gel-phase absorptiometry by employing smaller volume cell and a gel-aliquoting device are carried out in order to determine silicic acid in highly purified water, in which the absorbance of Molyb-

] 87 denum Blue adsorbed on Sephadex G-25 is measured directly. The gel amount used was reduced to one-sixth. Less than 0.05 g of the gel could be measured rapidly with good reproducibility and the detection limit of silicon was 0.04 gg/1. The method is more sensitive than other reported methods. - Anal. Sci. 9, 111 - 115 (1993). Res. & Environ. Protect. Res. Lab., NEC Corp., Miyazaki, Miyamae, Kawasaki 216 (J)

Determination of oxide ions in aluminium chloride-alkali chloride melts by Karl Fischer titration. H. Kurayasu and Y. Inokuma. Oxide ions can be simply and precisely determined in acidic aluminium chloride-alkali chloride melts (57 - 63 % A1C13)by Karl Fischer titration. Oxide ions were capable of reacting quantitatively with the Karl Fischer reagent when a melt sample was directly injected into the reagent. Oxide ions in eutectic A1C13-NaC1-KC1 melts (61:26:13 mol%) were determined with a relative standard deviation of less than 4%. The absorbances of infrared absorption bands observed over the range from 1200 to 1800 cm-1 in the spectra of eutectic melts were proportional to the oxide ion concentration determined by this method. - Anal. Chem. 65, 1210-1212 (1993). Iron, Steel Res. Lab., Sumitomo Metal Ind., Ltd., 1-8 Fusocho Amagasaki 660 (J) Trace gold determination in cyanide process solutions-preconcentration using supported liquid membranes in a flow-injection manifold. M.J.C. Taylor, D.E. Barnes and G.D. Marshall. To determine gold in cyanide process solutions a preconcentration of dicyanoaurate(I) anion is performed by extraction into a supported liquid membrane, formed by the in situ coating of a thin layer of organic phase onto a polymeric support. This support is packed into a minicolumn, which forms part of a flow injection manifold. After the sample solution has flowed over the organic phase for a suitable period, the entire organic phase is washed off the column with an organic solvent and introduced into the flame of a conventional atomic absorption spectrometer. Using 10 ml of 40 gg/1 sample, a 53-fold preeoneentration of gold was achieved in a load time of 120 s with Sr = 2.7%, sampling frequency 24 per hour. The method allows gold to be determined in the range of 0.01 to 0.1 mg/1 with a 2 - 7 % relative standard deviation at the 0.04 rag/1 level. With an analysis time of 150 s per sample, a detection limit of 0.005 mg/1 was achieved with a sampling frequency of 24 h - 1. _ Anal. Chim. Acta 265, 7 1 - 7 9 (1993). Mintek, Private Bag X3015, Randburg 2125 (ZA) Determination of bromide in sodium chloride matrices by flow-injection analysis using blank peak elimination and kinetic discrimination. W.J.M. Emaus and H.J. Henning. The flow-injection phenol red method was used for the determination of 0.5 - 10 rag/1 Br- in NaC1 solutions containing 300 g/1 or less of NaC1. The interference of chloride, forming chlorinated reaction products at a much slower rate than the reaction with bromophenol blue, is prevented in flow-injection analysis because of the short reaction times. The influence of blank peaks, which appear because of the difference in the refractive indices of the aqueous carrier solution and the sample solution, is eliminated by use of a large sample injection volume. The limit of quantification of bromide in sodium chloride is 1.0 mg kg- 1. The relative standard deviation at a level of 3 0 - 50 mg Br- kg- i is better than 1%. The characteristics of the method such as calibration, selectivity and ruggedness are described. The sample throughput is about 60 h-1. _ Anal. Chim. Acta 272, 245-250 (1993). Dept. Anal. Chem., Akzo Salt, Basic Chem. Div., 7550 GC Hengelo (NL) High-performance liquid chromatographic determination of aluminium and iron(III) in solar salt in the form of their 1-phenyl-3-methyl-4-benzoyl-5pyrazolone (PMBP) chelates. Y. Akama and A. Tong. The use of PMBP as a precolumn derivatizing agent for the mutual separation and detection of A1 and Fe(III) by HPLC in solar salt samples is reported. The samples were dissolved in dilute nitric acid with heating. An aliquot of the solution was pipetted and adjusted to pH 3 with acetate buffer, then 10 ml of 0.02 M PMBP-methanol solution were added. The chelates obtained were dissolved in dioxane and J0 gl were injected and analysed by HPLC on a Chemcosorb 5-ODS-UH column with methanol as mobile phase. The determinations were completed within 20 min and the recoveries of each metal were satisfactory. Divalent metal ions did not

188 interfere under the same chromatographic conditions. - J. Chromatogr. 633, 129-133 (1993). Dept. Chem., Fac. Sci., Engin., Meisei Univ., Tokyo 191 (J) ln-situ analysis of nitrogen in minerals. A.M. Bastoul, J. Pironon, M.

Mosbah, M. Dubois and M. Cuney. Three microscopic techniques are applied to the in-situ analysis of nitrogen trapped as ammonium ions in silicate minerals (muscovite, biotite, feldspar). Spectra obtained with Fourier transform infrared microspectroscopy show vibrational vl, v2, v3 bands and some overtone and combinations of the ammonium molecule. The quantitative analysis needs the use of natural or synthetic silicate standards. The ammonium ion of the analysed sheet minerals is not detected by Raman microspectroscopy. The nuclear microprobe is applied on the same mineral preparation and nitrogen content is measured using the 14N(d,%)12C and ~4N(d,po)~SN nuclear reactions with a deuteron energy of 1.8 MeV. TiN is used for calibration; concentrations from 360 to 2200 ppm are obtained. The ion microprobe has similar application fields as the nuclear microprobe, but is more sensitive to matrix effects. the isotopic composition cannot be obtained considering the sensitivity of these techniques to the low lSN content of minerals (near ] to 10 ppm). The detection limit lies between 10 and 100 ppm, and is similar to the detection limits of the bulk techniques. - Fur. J. Mineral. 5, 233-243 (1993). CREGU, BP 23, 54501 Vandoeuvre-16s-Nancy (F) Simultaneous determination of the major and minor elements in high-purity mullite by XRF analysis. T. Maruta, S. Yokoyama, H. Kobayashi and T. Yamane. A simple, rapid method for the simultaneous determination of the major and minor elements in high-purity mullite by XRF analysis is presented. The preparation of glass-bead samples with a lower dilution factor was studied in order to improve the stability of XRF measurements and analytical sensitivity. A 1.5 g sample was fused with a 4.5 g flux (mixture of LiBO2 and Li2B~O7 in a 1 : 1 ratio) in a platinum crucible containing 5 % Au at 1100°C for 6 rain. Lithium bromide (75 gl of 50% solution) was added into a flux as a removing additive. The proposed method was applied to the simultaneous determination of AI203, SiO2, ZrO2, MgO, TiO2, Na20, CaO, Y203, Fe203, K20, HFO2 in highpurity mullite; the results agreed well with those obtained by ICP-AES • analysis. Bunseki Kagaku 41, 589-592 (1992); (Orig. Jap.) Dept. Chem., Fac. Educ., Univ., Kofu-shi, Yamanashi 400 (J) Determination of ten rare earth elements in rare earth ores by inductively coupled plasma-atomic emission spectrometry. I. Roelandts. Comparing anion-exchange separation, cation-exchange separation and protocols without any chemical separation ores were analysed by ICP-AES for rear earth elements (REEs). Good agreement is generally achieved, the precision of the analytical data being better than 3%. Therefore the direct ICP-AES method is proposed as sufficient for the day-to-day routine analysis of REEs in REE-ores. - At. Spectrosc. 13, 193-198 (1992). Dept. Geol., Petrol., Geochem.-B20, Univ., B-4000 Sart Tilman, Liege 1 Analysis of rare earth elements (REE) in silicates by ion microprobe using doubly-charged ions. L.R. Riciputi, W.H. Christie, D.R. Cole and T.M. Rosseel. The use of doubly-charged, odd-mass REE ions and a Cameca IMS4f ion microprobe for the quantitative analysis of REEs in minerals is described. The secondary ion spectra of the doubly-charged odd-mass REE are virtually free of interferences, allowing measurements to be carried out at low energies and without the need for spectral stripping. Calibration lines have been established for La, Pr, Nd, Sin, Eu, Gd, Tb, Dy, Er, Tm, and Yb using a suite of clinopyroxene standards. This technique offers a relatively fast, simple approach for the in-situ analysis of REE on spots of < 20 gm and detection limits of < 15 ppb for most elements. -- Anal. Chem. 65, 1186 - 1] 91 (1993). Nat. Lab., Oak Ridge, TN 37831-6365 (USA) Determination of rare earth elements (REEs) in geological materials by ICP-AES using an optimized ion-exchange separation procedure and ultra-

2

Particular matrices and fields of application

sonic nebulization sample introduction. I.B. Brenner, R. Binstock, E. Dorfman and L. Halicz. Various protocols for the determination of REEs in geological and environmental materials by ICP-AES with special regards to the preenrichment using off-line cation exchange chromatography are discussed. Best results were obtained using a mixture of acids (HNO3-HC1) concerning the elution efficiency of the elements, the discrimination between light and heavy REEs and the separation of the matrix and other interfering elements as well as a reduction in acid volumes. The sample throughput can be drastically increased. With ultrasonic nebulization sample introduction in comparison to pneumatic nebulization a 10-fold enhancement of the detection limits can be obtained with comparable accuracy and precision. Due to the low salt concentration ultrasonic nebulization sample introduction can be easily applied. Direct determination of REEs is investigated with emphasis on line selection taking into account minimum interference, maximum signal to background ratios and low limits of detection. Data for standard reference materials are given. - ICP Newsletter 18, 473 -478 (1993). Geochem. Div., Geol. Survey Israel, Jerusalem (IL) Determination of beryllium by ICP-AES in beryl samples and silicate rocks. G.S. Chowdary, K. Satyanarayana and Neerja Mathur. The determination of beryllium in beryl samples and silicte rocks using a sequential ICP-AED is described. Optimized parameters for the forward power, the observation height and sample gas flow according to signal to noise background ratios are given. All five emission lines are used for the determination, they are in good accordance to each other. At. Spectrosc. 13, 213-216 (1992). At. Min. Div., Dept. At. Energy, Begumpet, Hyderabad 500116 (IND) Sequential determination of molybdenum and tungsten in silicate rocks by a spectrophotometric method. Zhen-Hai Fan, Li-Xing Zhang and HuiDe Zhou. A procedure for the sequential determination of Mo and W is proposed which is based on the fact that the metal complexes with toluene3,4-dithiol are formed under different acidity conditions. The Mo-dithiol complex is formed at high acidities and can be extracted and separated from W in CC14. The procedure proposed has been successfully used to determine molybdenum and tungsten in granite. The results show that this method can accurately determine molybdenum and tungsten down to the gg g- 1 and sub-gg g - 1 level with relative standard deviations of 1% and 3.5%, respectively. - Anal. Chim. Acta 270, 267-269 (1992). Northwest Inst. Nucl. Technol., Xian 710000 (RC) Determination of Fe, Mn, Ni and Sc in olivine by secondary ion mass spectrometry. S. Weinbruch, S. Specht and H. Palme. Relative sensitivity factors for SIMS analysis of Fe, Mn, Ni, and Sc in olivine were determined as function of FeO content ( 0 - 1 7 wt.%). The application of these data to the analysis of trace elements in forsterite is described. Determination of low concentrations of Fe, Mn, Ni and Sc in olivine with SIMS (applying high mass resolution) is straightforward (detection limits on the order of 100- 200 ppb are easily obtained). The use of a well defined set of standards to obtain accurate results is strongly recommended. SIMS measurements of trace elements in olivine are characterized by high precision (depending on concentration, relative standard deviations lie between 0.5 and 30%) and high accuracy. - Eur. J. Mineral. 5, 37-41 (1993). Max-Planck-Inst. Chem., W-6500 Mainz

(D) Gold determination in geological materials by amyl acetate extraction and flame AAS. R.A. Davidson. An AAS method was developed for the determination of gold in geological materials and metallurgical test products. Gold can be determined over a wide concentration range from 0.00I to several hundred gram per ton in samples of very different origin. Samples are pulverized, roasted to oxidize any sulfide and/or carbonaceous material and then subjected to a series of acid attacks to eliminate the silica matrix and to dissolve and further oxidize the sample. The digestion is continued by a bromine attack, the resulting bromoaurate complex being extracted into amyl acetate, which can be analysed by AAS. Nugget effects and interferences from iron are discussed. The accuracy of the method is verified

2.1

189

Inorganic geological materials

by different interlaboratory tests. - At. Spectrosc. 13, 199-205 (1992). U.S. Dept. Interior, Bur. Mines, Res. Cent., Salt Lake City, UT 84108 (USA) Flow-injection on-line fibre column separation and preconcentration system for efficient determination of trace gold in ores and metallurgical samples by flame atomic absorption spectrometry. Weiyi Qi, Xing Wu, Chun Zhou, Haizhou Wu and Yingqi Gao. For the trace determination of gold above 0.01 g/t in ores and metallurgical samples a flow-injection on-line 853• fibre column separation and preconcentration system is proposed. A flow manifold with a pump and two valves was assembled to conduct the operating cycle of equilibrationpreconcentration-washing-elution automatically in sequence. A 40 mm long column is recommended. The detection limit (3c0 of the proposed method was 0.2 ng m l - 1 gold and the relative standard deviation was 6% (n = 11) for 1 ng m l - 1 and 2.2% (n = 7) for 80 ng m l - 1 gold. About 4 0 - 6 0 injections can be performed per hour. - Anal. Chim. Acta 270, 205-2•• (1992). Dept. Anal. Chem., Gen. Res. Inst. Non-ferrous Metals, Beijing •00088 (RC) Determination of gold(I) and silver(I) cyanide in ores by capillary zone electrophoresis. M. Aguilar, A. Farran and M. Martinez. Capillary zone electrophoresis (CZE) with on-column UV detection at 214 nm was used to detect and determine gold(I) and silver(I) cyanide complexes in alkaline cyanide solution. The advantages is the direct use of leaching solutions to the CZE. Under an applied voltage of 25 kV, dicyanoaurate(I) and dicyanoargentate(I) were separated in less than 6 min. Carbonate buffer was used and the separation of both anions was achieved using an anodic injection and cathodic detection scheme. The method was applied to the determination o f gold and silver cyanide in ore samples. Quantitative analysis was possible and good agreement between CZE and atomic absorption spectrometric results was obtained. - J. Chromatogr. 635, 127-131 (1993). Dept. Chem. Engin. (ETSEIB-UPC), 08028 Barcelona (E) Flotation-spectrophotometric determination of gold in gold ore, anodic slime and cyclone dust using iodide and methylene blue. M. Balcerzak. Gold in dilute HC1 and in the presence of an excess of iodide reacts with Methylene Blue (MB) giving a sparingly soluble ion associate [(MB+)(AuI2-)]. The ion associate is separated in a form of precipitate when an aqueous solution is shaken with cyclohexane. Gold is quantitatively floated at 1.5 × 10 - 4 mol 1- 1 MB and above 1.5 × ] 0 - 3 tool 1- 1 KI. The ion associate [(MB+)(I3-)] is floated simultaneously. Methanolic solutions of the ion associates separated obey Beer's law up to 1.0 gg Au in 1 ml. A molar absorptivity (a) equals to 1.9x 105 1 tool -1 cm 1 ()~.... = 660 nm); a relative standard deviation (st) is 1.5 1.8%. Gold (at the level 1 0 - 3 _ 10-5 %) in ore, anodic slime and cyclone dust was determined with the developed method. The samples of gold ore and cyclone dust were preliminary treated with H F and HNO3; of anodic slime with HzSO,, HNO3 and CH3COONH4. Gold was extracted by ethyl acetate after dissolving in aqua regia. Chem. Analit. 37, 6 8 3 690 (1992). Dept. Anal. Chem., Techn. Univ., 00-664 Warszawa (PL)

The polarographic behaviour of 2-mercaptobenzothiazole (MBT) in strongly acidic medium is investigated and used for the catalytic polarographic determination o f trace amounts of tungsten. The tungsten-MBT complex yields a sensitive catalytic hydrogen wave at - 1 . i 0 V (vs. SCE) in strongly acidic medium. The peak height is a linear function of tungsten concentration over the range 0.004-1.4 gg/ml in 0.9 M H 2 S O 4 - 2 0 mg/ml N a C I - 0 . 0 1 gg/ml MBT medium. The method can be applied for determination of trace amounts of tungsten in geochemical materials. - Talanta 39, 1 1 9 - 1 2 2 (1992). Dept. App. Chem., Coll. Geol., Chengdu, Sichuan (RC) Ion chromatography of sulfur dioxide, sulfate ion, and dithionate ion in aqueous mineral leachates. L.M. Petrie, M.E. Jakel, R.L. Brandvig and J.G. Kroening. Sample preparation included the application of a pH 2.44 buffered diluent containing formaldehyde to prevent the Mn2+-catalyzed oxidation of S(IV) to SO42-. The method is applicable for all samples containing M n 2 +, Fe 3 +, and other metal catalysts. The IC method for $2062- may be useful for environmental samples as well. - Anal. Chem. 65, 9 5 2 - 9 5 5 (•993). Bureau Mines, U.S. Dept. Interior, Minneapolis, M N 554•7 (USA) A low dilution fusion technique for the analysis of geological samples. 2 - Major and minor element analysis and the use of influence]alpha coefficients. J. Eastell and J.P. Willis. Major and minor elements in geological samples are determined using low-dilution fusion techniques. The sample preparation technique uses a single homogeneous glass disc, the loss of the volatiles being determined by a loss on fusion (LOF) technique. The glass disc has a flux-to-sample ratio of 2:1. Three methods of calculating appropriate ~ coefficients have been investigated, namely (1) multiple regression analysis, (2) the Norrish and Hutton method and (3) a computer program, NBSGSC, involving fundamental parameters and the COLA equation. Methods (1) and (2) gave poor results for rock types of widely varying composition. The third method requires that the variation of czcoefficients with varying weight fraction of the analyte element be taken into account when calculating such coefficients. - X-Ray Spectrom. 22, 7 1 - 7 9 (1993). Geochem. Dept., Univ. Cape Town, Rondebosch, 7700 (ZA) Selective determination of yttrium in geological materials by ion-interaction chromatography. R. Kuroda, K. Sato and K. Oguma. Selective separation and determination of yttrium in rare earth ores have been achieved by high performance ion-interaction chromatography. Ores are decomposed by sulfuric acid and the rare earths are precipitated in a group as oxalates. Yttrium is then separated from the other rare earths on a C-18 bonded phase silica column modified with l-octanesulfonate by linear concentration gradient elution for 20 rain with 0.15 to 0.40 M glycolic acid (pH 3.5). Yttrium elutes at about i0 min between samarium and neodymium, being separated selectively from all the rare earths as well as scandium, thorium and uranium. Postcolumn reaction detection and quantitation with Arsenazo III [2,7-bis(2arsonophenylazo)-l,8-dihydroxynaphthalene-3,6-disulfonic acid] are carried out at 650 nm. - Mikrochim. Acta 110, 4 7 - 5 3 (1993). Lab. Anal. Chem., Fac. Engin., Univ., Chiba 263 (J)

Sub-stoichiometric isotope dilution analysis for the determination of thallium by liquid scintillation counting. N. Rajesh and M.S. Subramanian. A sensitive and selective sub-stoichiometric isotope dilution method for the determination o f trace amounts of thallium is described, employing the ion-association complex with Victoria Blue B into toluene from 0.5 mol 1-1 HC1. The [3-activity of thallium-204 was measured by liquid scintilation counting. The counting efficiency was found to be 95%. The calibration graph was linear in the range 0 - 4 gg ofT1 m in a final volume of 30 ml. The method is sensitive down to 0.2 gg ofTI m in a final volume of 30 ml. The interferences of Hg n, Sb m, A S lI! and Mo vi were overcome by collecting thallium on PbS. The method was found to be useful for the determination of thallium in flue dust, zinc ore, zinc base die castings, rock samples, cadmium turnings and cabbage leaf samples. Analyst 117, 1953--1955 (1992). Dept. Chem., Inst. Technol., Madras 600 036 (IND)

Voltammetric trace determination of uranium and other transition metals in rock phosphate samples. N. Verma and K.S. Pitre. DCP, DPP and DPASV methods are used for the simultaneous trace determination of transition metals and uranium in rock phosphate samples. Water leaching followed by acid leaching of the finely powdered rock phosphate sample was used to prepare the analyte for analysis. Differential complexation with nitrilotriacetic acid was applied for better resolution of the polarographic waves. Uranium gave a well defined polarographic wave with E1/2 = - 0 ; 8 2 V versus SCE. The proposed voltammetric methods are capable of giving both qualitative and quantitative analyses of rock phosphate. The accuracy o f the methods was compared with AAS and X R F techniques. - Analyst 118, 6 5 - 6 9 (1993). Dept. Chem., Sagar-470 003 (M.P.) (IND)

A new catalytic polarographic system for determination of trace amounts of tungsten. Dezhong Dan and Jun Re.

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190 2.2

2

Organic materials

Pyrolisis-gas chromatographic atomic emission detection for sediments, coals and other petrochemical precursors. J.A. Seeley, Y. Zeng, P.C. Uden, T.I. Eglinton and I. Ericson. One-line flash pyrolysis coupled to a capillary gas chromatograph can be used for the charakterization of marine sediments, coals and other heterogeneous solid samples. A helium microwave-induced plasma is applied for chromatographic detection by AES. Simultaneous multielement detection is achieved with a photodiode array detector. The optical path of the GC-AES is purged with helium allowing simultaneous, sensitive detection of atomic emission from sulfur 181 nm, phosphorus 186 nm, arsenic 189 nm, selenium 196 nm and carbon 193 nm. Several sediment and coal samples have been analysed for their carbon, nitrogen, sulfur, oxygen, phosphorus, arsenic and selenium content. - J. Anal. At. Spectrom. 7, 9 7 9 - 985 (1992). Dept. Chem., Lederle Grad. Res. Tower A, Univ., Amherst, MA 01003 (USA) Determination of vanadium in coal fly ash by electrothermal atomic absorption spectrometry. S.S. Bhattacharyya, S.R. Dan(Biswas) and A.K. Das. A sensitive method for the determination of vanadium in coal fly ash by ET-AAS is described. Vanadium is separated using a monothio ~diketo liquid chelating exchanger (LCEH) in chloroform medium. The reaction parameters, i.e., pH, solvent, kinetics of extraction and the effects of various ions have been optimized as well as the instrumental conditions. The detection limit was found to be 0.58 ng. The accuracy of the method has been tested using reference samples. - Anal. Letters 26, 295-308 (1993). Dept. Chem., Univ., Burdwan 713 104 (IND) Determination of titanium in coal fly ash by ETAAS. S.S. Bhattacharyya, R. Chakraborty and A.K. Das. An ET-AAS method for the determination of titanium in coal fly ash using palladium acetate as a chemical modifier has been described. The instrumental conditions, graphite furnace programme, concentration of the modifier, interferences, the calibration and standard addition graphs were optimized. The limit of detection was 0.66 ng and the RSD was 2.4% for 10 determinations. The reliability of the method has been demonstrated by analysing a standard reference material. - Anal. Letters 26, 341-355 (1993). Dept. Chem., Univ., Burdwan 713 104 (IND) HPLC coupled with ICPMS for the determination of metalloporphyrins in coal extracts. W. Pretorius, M. Foulkes, L. Ebdon and S. Rowland. HPLC-ICPMS has been applied to the analysis of gallium porphyrin distributions in extracts of three standard coals. A schematic representation of the HPLC-ICPMS system used is given. Interferences resulting from the mobile phase are investigated. The HPLC-ICPMS results are compared with results obtained by HPLC-UV/VIS. The presence of gallium has been confirmed in all the porphyrin macrocycles. - J. High Resolut. Chromatogr. 16, 157-160 (1993). Dept. Environ. Sci., Univ., Plymouth PL4 8AA, Devon (GB) Prediction of gas chromatographic retention data for hydrocarbons from naphthas. T.F. Woloszyn and P.C. Jurs. A general model capable of predicting gas chromatographic retention indices for hydrocarbons in petrochemical mixtures is developed for two different stationary phases, SE-30 and Carbowax 20M. The models had relative standard errors in the range 1 - 2 % . This quantitative structureretention relationship (QSRR) study focused on a relatively heterogeneous data set and resulted in the generation of several statistical models that related Kovfits' retention index with descriptors that encode molecular structure. Also investigated was the addition of boiling point as a physico-chemical descriptor. These models bore a significant improvement over the models containing only structural descriptors, with R values of 0.996. -- Anal. Chem. 65, 582-587 (1993). Dept. Chem., The Penns. State Univ., 152 Davey Lab., University Park, PA 16802 (USA) Recent advances in polyolefin additive analysis. R.C. Nielson. The ultrasonic bath extraction and recovery of the phosphite ester, Irgafos 168, using various extraction solvents in high density polyethyl-

Particular matrices and fields of application

ene is described. The use of solvents such as cyclohexane and methylene chloride with an ultrasonic bath provides for a fast, reproducible method to extract these phosphite esters out without risking hydrolysis breakdown. Conventional acetonitrile/water reverse phase gradient techniques are discussed, as well as the use of normal phase, isocratic separations in under seven minutes. Flow programming can further optimize selectivity and resolution of the LC analysis. - J. Liquid Chromatogr. 16, 1625-1638 (1993). Waters. Chromatogr. Div., Millipore Corp., 34 Maple Street, Milford, MA 01757 (USA)

Evaluation of coating materials used on piezoelectric crystals for the detection of dimethyl sulfide in liquefied petroleum gas. K. Hawkesworth and J.F. Alder. Coated piezoelectric crystals were applied to the detection of the dimethyl sulfide (DMS) and its oxidation products, dimethyl sulfoxide (DMSO) and dimethyl sulfone (DMSOz) in a butane carrier gas stream. Over 39 stationary phase, metal and lipid multibilayer coating materials have been evaluated for potential gas detection of the target analytes. Good reversibility and fast response times (2 s - 2 rain) were exhibited by all coating materials evaluated but sensitivity towards DMS was poor. Best results were obtained with squalane as coating. DMSO could be detected with this sensor down to 10 ppm in butane reversible with a response time of 2 s - 1 min. - Analyst 118, 395-400 (1993). Dept. Instr. Anal. Sci., UMIST, Manchester, M60 1QD (GB) Fast analysis of oxygen and sulfur compounds in gasoline by GC-AED. B.D. Quimby, V. Giarrocco, J.J. Sullivan and K.A. McC1eary. To determine the total sulphur content as well as the concentration of additives (oxygenated) in gasoline a GC-AED method is developed. A HP-5 film capillary with a temperature program from 40 to 200°C was used. The AED provides selective detection of oxygen and sulfur compounds. Because the response factors for sulfur and oxygen are largely independent of the type of compound, calibration and determination of total element content are simplified. The use of a 0.1 mm i.d. capillary column enables complete elution of the components of the gasoline in under 10 min. Detection limits of 50-100 ppm can be obtained for the oxygenated compounds. - J. High Resolut. Chromatogr. 15, 7 0 5 - 709 (1992). Hewlett-Packard Co, Little Falls Site, Wilmington, DE 19808 (USA) The development of less hazardous elnent mixtures for the liquid chromatographic separation of total polycyclic aromatic hydrocarbons in heavy hydrocarbon oil mixtures. Z.H. Khan, K. Marron and S.H. Assi. As safer eluent system for the chromatographic separation of heavy petroleum mixtures into concentrates is described. Mixtures of dichloromethane and petroleum spirit (12:88 V/V) and ethyl acetate and methanol (40:60 V/V) can be used after the initial nonpolar petroleum spirit eluent. The neW elutropic series was successfully applied to diesel and gas oils, lube raffinates, brightstocks, aromatic extracts, hydrocracker products, and atmospheric and vacuum residues. The relative precision of the technique was established at _+ 4.6% for a wide range of petroleum mixtures. - J. Liquid Chromatogr. 16, 1473-1487 (1993). Petr. Technol. Dept., Petrol. Petrochem. Mat. Die., Kuwait Inst. Sci. Res., P.O. Box 24885, KT-13109 Safat (KT) Determination of methyl tert. butyl ether (MTBE) in gasoline. J. Feldman and M. Orchin. A GLC-acid extraction method is described for the determination of MTBE in gasoline. MTBE is selectively extracted from the gasoline by 85% H3PO4 at 0°C and GLC of the untreated and extracted samples was carried out with toluene as internal standard on two film capillaries connected in series from 35° to 200°C. This treatment results in the preferential solubility of ethers and other oxygenated compounds while minimizing the reaction of olefins and aromatics. Plotting various known concentrations of MTBE in gasolines against the concentrations determined in the same samples results in a straight line relationship. The concentration of MTBE in any sample of gasoline may thus be determined. The analysis can accomodate a wide choice of standard GLC columns and programs. -- Anal. Letters 26, 357--365 (1993). Dept. Chem., Univ., Cincinnati, OH 45221-0172 (USA)

2.2

Organic materials

Experimental design optimization of the separation of the aromatic compounds in petroleum cuts by supercritical fluid chromatography. R. Fraile and V. Sfinchez. To optimize the determination of the aromatic content in aviation fuels a systematic experimental design approach is carried out based on the experimental matrix proposed by D.H. Doehlert [Appl. Statistics 19, 231 (1970)]. The resolution and analysis time can be changed by varying the pressure and temperature of the supercritical carbon dioxide mobile phase. The separation between saturated and aromatic compounds was optimized using only seven experiments. The analysis time required for determination of the total aromatic content of more complex samples can be reduced to less than 10 rain. - J. High Resolut. Chromatogr. 16, 169 - 174 (1993). Anal. Evaluation Dept., Intevep S.A., Caracas 1070-A (YV) Separation of polyaromaitc sulphur hydrocarbons (PSH) from petroleum fraction by ligand exchange chromatography. G. F~lix, M. Liu, P. Ithurralde, J. Goupy, J.M. Colin and M. Bouquet. A novel method for separation of polyaromatic sulphur hydrocarbons from petroleum cuts is described, based on ligand exchange chromatography using palladium salt grafted by a ionic way on silica gel. Hexane is used as mobile phase, after inversion of the flux the PSH can be eluted at 90°C. - Analusis 21, 153 - 156 (1993). ENSCPB/CNRS URA35, crs de la Lib6ration, 33405 Talence (F) On-line single column capillary gas chromatographic analysis of all reactants and products in the synthesis of fuel methanol from hydrogen and oxides of carbon. J.H. Marsman, B.B. Breman and A.A.C.M. Beenackers. A flexible on-line GC method with a single capillary column, temperature programmed, was used for complete analysis of reactants and products (hydrogen, carbon monoxide, carbon dioxide, water, Ca-C~0 hydrocarbons, and C 1 - C 6 alcohols): a sample selection valve is used to switch between either the heated line used for input of the synthesis gases or the heated line used to transport reaction products from the reactor. Sample is introduced to the capillary column by means of a 10-port heated gas sampling valve with two external injection loops (0.07 and ] .95 cm3). A wide range of concentrations in the sample (ppm to percentage levels) is determined with helium from a pressure-controlled supply as carrier gas and detection of the components is performed by serial connection of thermal conductivity and flame ionization detectors. Peak identification is performed by MS. The automated analytical equipment is integrated with a process control computer and delivers repeatable analytical results for the individual components (RSDs varying between 0.3 and 10%). - J. High Resolut. Chromatogr. 16, 141-147 (/993). Dept. Chem. Engin., Univ., 9747 AG Groningen (NL) Application of an automated interpretation system for infrared spectra. Part I. Automated qualitative analysis of polymers. Part II. Characterization of aromatic sulphone copolymers. J.A. de Koeijer, H.J. Luinge, J.H. van der Maas, J.M. Chalmers and P.J. Tayler. The possibility of the identification of homopolymers, copolymers and blends qualitatively from IR spectral data using a knowledge-based approach is tested. This is possibIe due to the automated generation of interpretation rules for the characterization of aromatic polymers. Peak tables obtained from diffuse reflectance and attenuated total reflectance spectra are used to generate these rules. In order to improve the information content of the peak tables the role of second-order derivative spectra is investigated. - Vibr. Spectrosc. 4, 285-308 (1993). Anal. Mol. Spectrom., Univ., 3508 TB Utrecht (NL) A new automated analysis system of polymers by pyrolysis GC. E. Saitoh, M. Hoshi, Y. Kondoh, H. Tokuda and K. Matsumoto. A new automated analysis system for the identification of a variety of polymers has been developed by using pyrolysis gas chromatography in conjunction with on-line data processing with a personal computer. A polymer sample was pyrolyzed at 670°C with a Curie point type pyrolyzer. The volatile pyrolyzates were separated on a fused silica capillary column (DB17) and monitored with a nitrogen phosphate detector (NPD) as well as a flame ionization detector (FID). The use of NPD gave the increased reliability of the identification of nitrogen-

191 containing polymers such as amino-modified silicones and quarternary ammonium salt type polymers because of its high selectivity for nitrogencontaining compounds. The pyrograms obtained were normalized by the use of retention indices in which olefin peaks produced by the pyrolysis of polyethylene were used as the reference for the calculation of the retention indices and then searched against a home-built database. Similar indices were introduced to make it easy to evaluate the similarities between sample pyrograms and standard ones in the database. A series of processes involved in the proposed method were fully automated. - Bunseki Kagaku 42, 119-125 (1993); (Orig. Jap.) Kao Corp., Res. Lab., Haga-gun, Tochigi, 321-34 (J)

Sequential optimisation of the separation of a complex mixture of plastics additives by HPLC with a quaternary gradient and a dual detection system. E. Lesellier and A. Tchapla. The separation of two families of plastics additives (phenolic antioxidants and UV absorbers) has been achieved by HPLC with a quaternary gradient composed of tetrahydrofurance, water, methanol and acetonitrile. A methodology of separation based on a sequential optimization is described. The importance of the column phase ratio is also reported. The use of two detectors, UV absorbance and lightscattering, enables all the compounds to be detected. - Chromatographia 36, 135-143 (1993). L.E.T.I.A.M., IUT d'Orsay, F-91403 Orsay Cedex (F) Separation of six polymer additives using mobile phase optimization software. E. Lesellier, P. Saint Martin and A. Tchapla. The use of a new solvent-optimization programme to determine an appropriate mobile phase composition with a minimum number of experiments is described for the separation of polymer additives which are poorly soluble in water. Six components of plastic packing additives have been chosen for separation, phenolic antioxidants like BHT, BHA, Irganox 1010 and 565 and two UV absorbants like Tunivin P and 327. The choice of the isoeluent mobile phase is based on the retention of the last eluted compound in every binary mixture. All optima points for the eluent composition determined using the developed software provided satisfactory separation of this six additives in a short analysis time. The software used was not operated under normal conditions because THF was chosen as the basic solvent instead of water. The software worked as well for partially aqueous reversed-phase as for non aqueous reversed phase liquid chromatography. - LC-GC Intern. 5, 38 - 4 3 (1993). Lab. Etudes Techn. Instr. Anal. Molecul., Inst. Univ. Technol., F-91403 Orsay Cedex (F) Spectroscopic separation of perfluorinated liquid mixtures using two-dimensional NMR. W.I. Bailey, A.L. Kotz, P.L. McDaniel, D.M. Parees, F.K. Schweighardt and H.J. Yue. To identify components in complex perfluorinated mixtures two-dimensional 19F-NMR techniques with homonuclear relayed coherence transfer (COSYRCT) is an effective tool. A comparison between homonuclear Hartmann Hahn and COSYRCT is carried out. The ability to extract one-dimensional 19F spectra of"pure" individual components from both the 2-D HOHAHA and COSYRCT experimental specta and their unique advantages, disadvantages, and limitations as tools for spectroscopic separation of complex liquid mixtures were demonstrated. - Anal. Chem. 65, 752-758 (1993). Air Prod. Chem., Inc,, Allentown, PA-18195-1501 (USA) Time-of-flight secondary ion mass spectrometry (TOF-SIMS) of poly(alkyl methacrylates). P.A. Zimmerman, D.M. Hercules and A. Benninghoven. TOF-SIMS has been used to gain insight about polymer fragmentation not available from other methods. Data obtained for acrylic polymers are used to study mechanisms for chain decomposition and structures. Anal. Chem. 65, 983-991 (1993). Dept. Chem., Univ. Pittsburgh, PAl 5260 (USA) Separation of some nonylphenyl ethylene oxide oligomers according to the length of the ethylene oxide chain. T. Cserhfiti. The separation of non-ionic surfactants such as nonylphenyl ethylene oxide oligomers according to the length of the ethylene oxide chain has

192 been performed on precoated alumina thin layer plates using chloroform/acetonitrile mixtures as eluents. The longer the ethylene oxide chain, the higher the acetonitrile concentration needed to achieve optimum separation. - J. Planar Chromatogr. 1, 7 0 - 7 3 (1993). Centr. Res. Inst. Chem., Hung. Acad. Sci., P.O. Box 17, H-1525 Budapest (H)

Determination of free toluene diisocyanates in flexible polyurethane foams using negative chemical-ionization mass spectrometry. K. Jedrzejczak and V.S. Gain& A highly sensitive and specific procedure is described for the determination and confirmation of traces of toluene diisocyanate (TDI) in polyurethane foams by NICI-MS and SIM. Foam samples were extracted with methanol after addition of deuterated toluene-2,4-diyl dimethylcarbamate as an internal standard. The extracts were concentrated, derivatized with pentafluoropropionic anhydride at 70°C and analysed by capillary column gas chromatography on a DB-5 capillary with a temperature programme from 80 to 250°C. The limit of detection was 10 ng g-1 for a 1.0 g sample. The recovery was above 79% and reproducibility assessments indicated good accuracy and precision with relative standard deviations ranging between 4.3 and 8.5% over the concentration range of 20 - 500 ng g 1. The method was applied to the determination of free TDIs in fresh foam samples. - Analyst 118, 149152 (1993). Occ. Health Lab., Ontario Min. Labour, Weston, Ontario, M9P 3T1 (CDN) Quantitative determination of sodium lauroyl sareosinate by gas chromatography. K. Molever. A simple and rapid procedure is described for the isolation, silylation and wide-bore capillary gas chromatographic quantitation of sodium lauroyl sarcosinate in personal care products. The sample is dissolved in acidified dimethylformamide to simultaneously acidify extract the lauroyl sarcosine; an aliquot is then derivatized with bis trimethylsilyltrifluoroacetamide and quantitated by widebore capillary gas chromatography with flame ionization detection on a 12 m methyl silicone film capillary with a temperature program from 1 5 0 - 270°C. JAOCS 70, 101-103 (1993). Res. Develop. Dept., The Dial Corp., Seottsdale, AZ 85254 (USA) Determination of colloidal electrolytes: amperometric titration of dodecylpyridinium bromide with hexachlorostannate(IV) anion. R. Mikulski. A solution containing from 0.329 to 43.68 mg of dodecylpyridinium bromide (DDPyBr) in 20 ml sample, can be titrated amperometricaly with SnCI62- anion in 0.5 tool 1 1 NH4C1 as the supporting electrolyte applying voltage E = - 0 . 7 V or E = - 1 . 2 V. The amperometric titration curves had a typical shape corresponding to nonreducible subtances titrated with a reducible agent at E = --0.7 V and to reducible substance titrated with a reducible agent at E = 1.2 V vs. SCE. The possibilities of the amperometric titration of dedecylpyridinium bromide in presence of other organic and inorganic compounds were also investigated. - Chem. Analit. 37, 459 -463 (1992). Inst. Chem., N. Copernicus Univ., 87-100 Torufi (PL) Polarographic and chromatographic determination of monomers released by the unprocessed and processed phenolic plastics. I. Zjawiony. Free phenol, formaldehyde, and methanol, released during ageing of selected processed and unprocessed phenolic plastics, were determined using polarographie and chromatographic methods. Investigations were performed for isolated samples in atmosphere in the temperature range 20-65°C, and also under conditions of continuous flow of air over polymeric phases. The exponential dependence was found between the mass of evolved compound and temperature. The presented investigations can be treated as a proposition of testing both the toxicity and usefulness of unprocessed and processed phenolic plastics. - Chem. Analit. 37, 559-568 (1992). Sect. Phys. Chem., Inst. Chem., Silesian Univ., 40-007 Katowice (PL) Determination of an organotin stabilizer in a rigid poly(vinyl chloride) plastic by on-line supercritical fluid extraction and chromatography with formic acid modified carbon dioxide and flame ionization detection. J.W. Oudsema and C.F. Poole.

2

Particular matrices and fields of application

The applicability of SFE and SFC for dialkylorganotin stabilizer in rigid PVC plastics using formic acid modified carbon dioxide as extraction solvent and mobile phase for chromatography is demonstrated. Concentrations of 1.45% (calculated as dimethyltin) can be determined with an RSD of 2.9% (n = 6). - J. High Resolut. Chromatogr. 16, 198 202 (1993). Dept. Chem., Wayne State Univ., Detroit, MI 48202 (USA)

Analytical study of highly condensed non ionic surfactants. Separation on cation exchangers. B. Desmazi~res, F. Portet and P.-L. Desb~ne. Complex mixtures of polyoxyethylenic chains like in surfactants as Brij 99 and KM25 can be separted by ion chromatography on a partially ionized silica phase, conditioned in different ways. The influence of the nature of cations on the separation selectivity was studied. Cations studied included alkali metals (Li +, Na +, K +, Rb +, Cs +), alkaline earth metals (Mg 2+, Ca 2+, Sr 2+, Ba 2+), transition metals (Zn2 +, Cd 2+, Hg2 +, Pb 2+, Cu2 +), and quaternary ammonium NH4 +, NMe4 +) ions as well as a proton (acetic acid). The influences of ionic strength, pH and addition of cosolvent were examined. The optimized conditions [mobile phase: CH3CN/H20 (92/8), pH 7.4, sodium acetate 5 x 10 3 M; temperature gradient between 25 and 50°C] allowed for the first time the distributions of Brij 99 and KM 25 to be obtained. - Chromatographia 36, 307-317 (1993). Univ. Rouen, I.U.T., F-27000 Evreux (F) Determination of the degree of ethoxylation distribution of n-alcohol-EOadducts using high-resolution size exclusion chromatography. L. Mikolajczyk, W. Leukefeld and E. D6ring. Size exclusion chromatography is suitable for determining the ethylene oxide degree distribution for n-alcohol-EO-adducts from native fatty alcohols. Columns filled with gels on polystyrene basis were used with n-dodecanol as internal standard and RI detection. However, even high resolution cannot separate all these adducts. A method has therefore been developed to calculate the relevant information from the chromatographic signal. The efficiency of this analytical and mathematical method is demonstrated for three products with different degrees of ethoxylation (EO max = 30). - Tenside Surf. Det. 30, 3 4 - 3 8 (1993). Schkopau (D) Determination of monomer residues in polymer detergent co-bnilders by analytical capillary isotachophoresis. J. Silha and J. ~t~tina. The separation of monomer residues (acrylic, maleic and fumarie acids) in polycarboxylic acids was carried out using capillary isotachophoresis in the system of 10 mM HCI, 5 mM [3-alanine, 0.1% MHEC (m/m); (LE, pH 3.0) and 10 mM CH3COOH; (TE, pH 3 4). Effective separation was achieved over a wide range of polymer composition and mean molecular mass. Monomer residues were determined on different levels of their content. - Tenside Surf. Det. 30, 24 28 (1993). Prag (Czech Republic) Comparison of different ion sensitive electrodes for the titrimetric determination of ionic surfactants. N. Buschmann and R. Schulz. Six different ion sensitive electrodes (ISEs) were compared with regard to their suitability for the potentiometric indication of surfactant titrations. More than 500 titrations were carried out for the evaluation of the standard deviations of the equivalent volume and of the equivalent potential, the height of the potential jump and the number of faulty titrations. The behaviour of the electrodes was assessed with regard to their usefulness in routine analysis. The best results were achieved with a new surfactant sensitive electrode which has only recently come on the market. Electrodes specially designed for surfactant titrations do not need conditioning before use. Only for the electrode ASTEC-TSE 01/09 no reconditioning is necessary. - Tenside Surf. Det. 30, 1 8 - 23 (1993). Anorg. Chem. Inst., Lehrst. f. Anal. Chem., W-4400 Mfinster (D) Determination of betaine and free amine in alkyldimethyl betaine by potentiometric titrations. J.M. Plantinga, J.J. Donkerbroek and R.J. Mulder. Two titrimetric methods are presented for the selective determination of betaine and free amine contentens, respectively, in commercial alkyl dimethyl betaines without interferences by monochloroacetic acid and glycolic acid. After dissolution of the sample in 2-propanol some HC1 is added to convert betaine to the acidic form, the titration is carried out

2.2

Organic materials

potentiometrically with 0.1 mol/1 KOH. For the amine determination the sample is dissolved in water/2-propanol (1 : 1), NaOH is added and titrated with 0.1 tool/1 HC1. Recoveries of 99.4% for the amine with a standard deviation of 0.4% for the amine and 100,1% with 0,5% standard deviation for the betaine and a detection limit of 0.02% ( S / N - 3) for the amine are obtained. - JAOCS 70, 9 7 - 9 9 (1993). Akzo Chem. Div., Res. Centr. Deventer, Deventer (NL)

Photoacousticfc determination of sodium dodecyl sulfate concentrated on Empore TLC plate. K. Uchiyama, J. Minowa, Y. Yoshimura, T. Watanabe, K. Ohsawa and K. Imaeda. Photoacoustic determination of sodium dodecyl sulfate was proposed by the use of solid-phase concentration method with Empore plate. Sodium dodecyl sulfate was extracted as a Methylene Blue complex in chloroform. The chloroform extract of the water samples was filtered through the Empore plate (2.5 cm squares). Interfering methylene azures were eluted through the plate. The plate was cut into 13 mm circle and then photoacoustic signal was measured. By the pretreatment of the plate with sodium bicarbonate, the blank signal intensity was decreased to the half of the one without treatment. Linear relationship was obtained between the concentration of anionic surfactant and the photoacoustic intensity in the range 0 N 500 ppb. Detection limit of anionic surfactant was approximately 3.6 ppb. Analytical results were nearly equal to those by the JIS method. The recovery of anionic surfactants was in the range of 98.0~99.6%. - Bunseki Kagaku 41 649-653 (1992); (Orig. Jap.) Dept. Anal. Chem., Fac. Pharm. Sci., Hoshi Univ. 2-4-41, Ebara, Shinagawa-ku, Tokyo 142 (J) Determination of N-hydroxysuccinimidyl-activated polyethylene glycol esters by gel permeation chromatography with post-column alkaline hydrolysis. B. Shah and E. Watson. To determine N-hydroxysuccinimidyl-activated polyethylene glycol ester, the activated polyethylene glycol sample is first separated by sizeexclusion chromatography on a polymeric column with tetrahydrofuran as the eluent, and after elution is subjected to post-column on-line hydrolysis with 0.1 M sodium hydroxide. Liberation of N-hydroxysuccinimide occurs rapidly and is monitored by UV detection at 266 nm. The amount released is determined from a standard curve generated from free N-hydroxysuccinimide and used to calculate the concentration of active ester initially present. - J. Chromatogr. 629, 398-400 (1993). Amgen Inc., Amgen Cent., Thousand Oaks, CA 91320-1789 (USA) Rapid separation of non-ionic surfactants of polyethoxylated octylphenol and determination of ethylene oxide oligomer distribution by CI column reversed-phase liquid chromatography. Zhendi Wang and M. Fingas. A rapid, simple and reproducible reversed-phase HPLC method was developed for the separation and characterization of individual oligomers in polyethoxylated octylphenol (PEOP) surfactants with high resolution and sensitivity, using a C1 trimethylsilyl column. With this technique, oligomers of PEOP surfactants containing up to 40 ethylene oxide units (molecular mass distributions up to ca. 2000) were successfully resolved and identified. The effects of the mobile phase composition and of the solvents used to prepare PEOP surfactant solutions on the separation of oligomers were investigated in detail. As mobile phase a mixture of water + 0.02 g/1 ammonium acetate and 5 0 - 6 2 % methanol was used. The column effluent was monitored at 225 nm. - J. Chromatogr. 673, 145-156 (1993). Emergencies Sci. Div., River Road Environ. Technol. Cent., Ottawa, K1A 0H3 (CDN) Micellar electrokinetic capillary chromatography with cationic surfactants. D. Crosby and Z. El Rassi. A series of alkyltrimethylammonium chloride and bromide surfactants were evaluated in micellar electrokinetic chromatography (MECC) of urea herbicides, alkylbenzenes and phenylalkylalcohols. The separation of a mixture of six urea herbicides was best achieved when an MECC system of low hydrophobic phase ratio and wide retention window, such as docecyl- or decyltrimethylammonium chloride was used as the micellar phase. The overall separation of the urea herbicides could be enhanced by the inclusion of small amounts of octyltrimethylammonium chloride surfactant into the tetradecyltrimethylammonium chloride mi-

193 cellar phase. - J. Liquid Chromatogr. 16, 2161-2187 (1993). Dept. Chem., Univ., Stillwater, OK 74078-0447 (USA)

Determination of sodium dodecylbenzene sulfonate (DBS) using several internal standards by multivariate analysis of Curie-point, pyrolysis gas chromatography. M. Hida, S. Okuyama, T. Mitsui, Y. Minami and Y. Fujimura. Multivariate analysis is a useful technique for the quantitative analysis of DBS by pyrolysis GC. The programs obtained from mixtures of DBS and polyoxyethylene lauryl ether (PEG) were nomalized for the peak heights and areas of several internal standards which appeared in every pyrogram, against the characteristic peaks for DBS and PEG. This normalization method gave small experimental errors. The normalization values were used for cluster analysis unchanged. One calibration curve was calculated from the principal component scores. The DBS content of a sample was obtained from the calibration curve. Calculated values were in fair agreement with theoretical values. Chromatographia 35,643- 648 (1993). Criminal Sci. Lab. Aichi Prefect., Nagoya 460 (J) Gas chromatographic determination of nitro musks in cosmetics and detergents. C. Sommer. Methods for identification and quantitation of nitro musks in cosmetics and detergents have been developed. Cosmetics containing alcohol can be extracted with dichloromethane, all other products are extracted using a simultaneous destillation-extraction procedure with diethylether. The identification is carried out by means of GC/ECD and GC/MSD using a fused silica capillary (DB-17) with a temperature programme from 40 to 210°C. Musk ketone can be determined mainly in cosmetics whereas musk xylene is mainly used in detergents. - Dtsch. Lebensmittel-Rundschau 89, 108-111 (1993). Lebensmittel-, Veterin. Unters. Amt Schleswig-Holstein, W-2300 Kiel 1 (D) Analysis of N-phenyI-N'-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD) in aqueous migrates of rubber articles in contact with food by HPLC. H.J. Kretzschmar and V. Neyen. A new HPLC-method for determination of 6PPD is described. Because of low concentration in aqueous migrates a selective enrichment by using of solid phase extraction is indispensable. 6PPD is separated completely from other coeluents in a relative short time and is determined quantitatively by using an external standard. The HPLC was carried out on a C18 column with a gradient from 50 to 100% acetonitrile in phosphate buffer (pH 2.0). Recoveries > 90% were found. - Dtsch. Lebensm. Rundsch. 88, 387-390 (1992). Bundesanst. Materialforsch., -priif (BAM), 1000 Berlin 45 (D) Determination and speciation of chromium, copper and arsenic in wood and dust from CCA-impregnated timber. O. Nygren and C.A. Nilsson As preservatives contain Cu, Cr and As as the toxic Cr(VI) or As(III) speciation of these elemental forms is essential for quality control of impregnation and for the safety of the work environment during impregnation of timber. Methods as FAAS, GFAAS and spectrophotometry with a complete analytical scheme for the use for dust samples for determination of copper, chromium and arsenic and for speciation of hexavalent chromium, tri- and pentavalent arsenic are presented and examples given of the determination of these compounds in wood and dust from impregnated timber. The level of preservative in wood purchased from ten retailers was 1 . 5 - 3 % . Impregnated timber with improperly fixed preservative can cause hazardous occupational exposure and may also confer reduced long-term protection against microbial degradation. - Analusis 21, 8 3 - 8 9 (1993). Nat. Inst. Occup. Health, Res. Dept., Anal. Chem. Div., S-90713 Ume~ Evaluation of reversed-phase columns for the analysis of very basic compounds by high-performance liquid chromatography. Application to the determination of the tobacco alkaloids. D.V. McCalley. The best available stationary phases were tested for the RP-HPLC separation of the major tobacco alkaloids. Good results were obtained on a high-purity silica substrate, without use of silanol masking agents in the eluent. A test procedure based on that of Engelhardt and co-

194 workers, with pyridine as an additional probe compound, was used to aid the selection of a suitable stationary phase from a number of the best commercially available columns for the separation of strongly basic compounds. - J. Chromatogr. 636, 213-220 (1993). Dept. Chem., Phys. Sci., Univ., Bristol BS16 1QY (GB) Fluorimetric study of azolic protodyes in micellar media. E. Peris-Cardells, M. de la Guardia, E. Pramauro, P. Savarino and G. Viscardi. The fluorimetric determination of PAS-S and PAS-O in the presence of anionic, cationic or nonionic surfactants provides a sensitivity enhancement from 300 to 1800 per cent and a limit of detection of I ppb. Quire. Anal. 12, 3 8 - 4 4 (1993). Dept. Anal. Chem., Univ. Valencia, E46100 Burjassot, Valencia (E) Laser desorpfion laser photoionization time-of-flight mass spectrometry of dyes. M.J. Dale, A.C. Jones, P.R.R. Langridge-Smith, K.F. Costelio and P.G. Cummins. A two-stage desorption/ionization methodology is developed for the analysis of a wide range of neutral dye molecules. The mass spectra of a number of dye species have been investigated using two-step laser desorption laser photoionizatiom time-of-flight mass spectrometry. A pulsed COz laser, wavelength 10.6 gm, was used to vaporize the samples as intact neutral molecules which were photoionized using either 193or 266-nm laser radiation. Four classes of dyestuffs have been examined: azo, anthraquinone, phthalocyanine, and coumarin. The applicability of this mass spectrometric technique to the identification, characterization, and detection of aromatic dyestuffs ~s discussed. - Anal. Chem. 65, 7 9 3 - 801 (1993). Dept. Chem., Univ. Edinburgh, Edingburgh, EH9 3JJ

(GB) Spectrophotometric titration of some thiazine dyes with iron(II) in buffer medium in the presence of oxalate. K.V. Raju and G.B. Raju. An accurate and convenient spectrophotometric titration method was developed for the determination of microgram amounts of seven thiazine dyes employing iron(II) as a reductant in buffer medium (optimum pH 3.7-4.7) in the presence of sodium oxalate (optimum concentration 0 . 0 6 - 0.12 tool 1-1). All the dyes are rapidly and quantitatively reduced to their colourless leuco-bases in a two-electron reduction with iron(II). The redox potentials of the iron(III)-iron(II) couple in buffer media of different pH and oxalate ion concentrations were measured. A linear response was obtained in the range of 1.5 to 6.0 gg/ml for most of the investigated dyes. - Analyst 118, 101 - 104 (1993). Dept. Engin. Chem., Andhra Univ., Visakhapatnam 530 003 (IND) Reversed-phase high-performance liquid chromatography of sulphur mustard (HD) in water. C.D. Raghuveeran, R.C. Malhotra and R.S. Dangi. Aqueous samples containing sulphur mustard can be analyzed directly by HPLC using a guard column. A Polygosil C18 column with a RCSC18 cartridge were used with 63 % methanol and 75 % methanol, respectively. Detection was carried out at 200 nm. The detection based on the solubility of HD in water revealed that extremely low quantities of HD (4 to 5 rag/l) only are soluble. - J. Liquid Chromatogr. 16, 1615-1624 (1993). Def. Res. Develop. Establ., Tansen Road, Gwalior 474 002 (IND) Analysis of the explosive 2,4,6-trinitrophenylmethylnitramine (tetryl) in bush bean plants. S.D. Harvey, R.J. Fellows, D.A. Cataldo and R.M. Bean. A methodology for the analysis of tetryl in plant tissue has been developed based on solvent extraction of plant tissue followed by fractionation of the organic extract on silica gel with subsequent determination of tetryl by HPLC. This methodology allowed 82.70 _+ 5.54% recovery of tetryl from fortified bush bean leaves. The developed methodology was applied to study tetryl uptake and metabolism in bush bean plants exposed to tetryl-amended hydroponic cultures. - J. Chromatogr. 630, 167-177 (1993). Pacific Northwest Lab., Richland, WA 99352 (USA) Identification of degradation products of some chemical warfare agents by capillary electrophoresis]ionspray mass spectrometry. R. Kostiainen, A.P. Bruins and V.M.A. Hfikkinen.

2

Particular matrices and fields of application

CZE/IS-MS in the negative-ion mode was applied in the identification of five organophosphonic acids, which are the primary hydrolysis products of nerve agents. The spectra exhibit a very abundant (M - H ) - ion with minimal fragmentation. Fragment ions were produced by raising the nozzle-skimmer voltage difference in the first stage between the atmospheric pressure ion source and the mass analyzer. CZE/IS-MS provides extremely good separation efficiency and very high sensitivity for the phosphonic acids. Sensitivity in the range 10 - 30 pg was achieved with standard solutions using selected ion monitoring. Linear regression analysis data showed correlation coefficients to be between 0.994 and 0.999 in the range of 5 to 100 ng/gl. - J. Chromatogr. 634, 1 / 3 - 1 1 8 (1993). Univ. Cent. Pharm., Univ., 8713 AW Groningen (NL) Reference standards for quantitative trace analysis of PCB's by GC. Technical PCB formulations for the calibration of ECD and MSD responses. J. Krupcik, A. Kocan, J. Petrik, P.A. Leclercq and K. Ballschmiter. The method of secondary reference standards for calibration in PCB formulation analysis as described by the authors in Chromatographia 33, 514 (1992) is here used for calibration of ECD, MS-TIC and MSSIM responses. The responses of electron capture and selected-ion monitoring, mass spectra detectors can be calibrated for individual PCB congeners by correlation of the chromatographic patterns with those of concentrated PCB samples obtained by GC-FID. This procedure, which uses a given technical PCB formulation as a secondary reference standard mixture, is to be preferred over existing calibration methods, when results with _+10% errors are acceptable because commercial PCB formulations cover the whole range of chlorination products. - Chromatographia 35, 410-418 (1993). Univ. Ulm, Dept. Anal. Environmental Chem., W7900 Ulm (D) Isomeric characterization of polychlorinated biphenyls using gas chromatography-Fourier transform infrared[gas chromatography-mass spectrometry. D.M. Hembree, Jr., N.R. Smyrl, W.E. Davis and D.M. Williams. IR spectroscopy using low-temperature trapping (77 K) can be used as qualitative complement to conventional mass spectrometric detection of the effluent from a capillary column-gas chromatograph especially to the quantitative and qualitative characterization (including distinguishing positional isomers) of polychlorinated biphenyl (PCB) mixtures. This technique produces infrared spectra that resemble normal room-temperature condensed-phase spectra (as opposed to the gas-phase spectra produced by light-pipe gas chromatography-Fourier transform infrared spectroscopy) and leads to lower detection limits (500 pg for 3,3',4,5-tetrachlorobiphenyl). The GC-MS portion of the instrument provides superior quantitative capabilities with sub-picogram detection limits possible using selective ion monitoring. - Analyst 118, 249-252 (1993). Plant Lab., Oak Ridge Y-12 Plant, Martin Marietta Energy Syst., Inc., Oak Ridge, TN 37831-8189 (USA) Analysis of polychlorinated biphenyls, dibenzodioxins and dibenzofurans by on-line coupled microcolumn HPLC capillary GC-MS. K.J. Welch and N.E. Hoffman. The already described multidimensional gLC-GC-MS-system [K.J. Welch and N.E. Hoffman, J. High. Resol. Chromatogr. 15, 171 (1992)] was used to analyze a sample containing chlorinated aromatic solutes. The gLC-GC-MS system was demonstrated through the analysis of a sample containing polychlorinated biphenyls, 2,7-dichlorodibenzodioxin and 3,6-dichlorodibenzofuran. The precision for the quantitative transfer of an analyte from the pLC to the GC-MS was 16.9% RSD. -J. Liquid Chromatogr. 16, 307-313 (1993). Chem. Dept., Marquette Univ., Milwaukee, WI 53233 (USA) Interlaboratory study on the analysis of chlorobiphenyl congeners. J. de Boer, J.C. Duinker, J.A. Calder and J. van der Meer. An intercomparison study was carried out to determine the variation in the results of determinations of individual chlorobiphenyls (CBs) among participating laboratories. 62 laboratories from 16 countries participated in the first part of this exercise, which consisted of determining 10 CBs in a standard solution. Considerable emphasis was placed on optimization of the gas chromatographic analysis, which has led to

2.2

Organic materials

better agreement than former intercalibration exercises on CB analysis. Standard errors of 1.10-1.12 for the reproducibility were obtained for all CBs, except CB 52 for a group of 47 laboratories. The linear range of the electron capture detector was restricted to a factor of 5 in the concentration range 15-750 pg. - J. AOAC Intern. 75, 1054-1062 (1992). Inst. Fisheries Res., 1970 AB IJmuiden (NL)

Supercritical fluid extraction for the analysis of liquid poly(alkylene glycol) lubricants and sorbitan ester formulations. T.P. Hunt, C.J. Dowle and G. Greenway. Poly(alkylene glycol) (PAG) lubricant formulations and sorbitan ester formulations can be adsorbed onto silica and additives can be extracted through a silica column positioned in-line in the supercritical fluid stream. I g of samples can be analyzed. The obtained fractions can further be characterized by NMR without interferences from solvents. The selectivity obtained by this method was compared with that obtained by the direct extraction of adsorbed and unadsorbed PAG and by the extraction of unadsorbed PAG through the in-line column. The final procedure was found to be successful in separating additives from all but the lowest molecular mass PAG oligomers. - Analyst 118, 1 7 - 22 (1993). ICI Wilton Res. Cent., Middlesbrough, Cleveland, TS6 8JE (GB) Enzyme immunoassays for pesticide analysis. B. Hock. An overview over the basic principles behind immunoassays especially toward pesticides is given. Most examples are taken from the field of striazines. Common error sources, especially cross-reactivities and matrix effects, are discussed. Interlaboratory tests demonstrate the presently available quality of enzyme immunoassays. An outlook is given on future developments. 27 References. - Acta hydrochim, hydrobiol. 21, 71 - 8 3 (1993). TU Miinchen, Lehrst. Botanik, W-8050 Freising 12 (D) Utilization of a benchtop mass spectrometer with capillary supercritical fluid chromatography. B. Murugaverl, K.J. Voorhees and S.J. DeLuca. The feasibility of converting a commercially available benchtop GCMS system into a SFC-EI-MS system using a simple interface is investigated. The SFC-EI-MS of the thermally labile pesticides aldicarb, diuron, methiocarb, alachlor, bendiocarb, and carbaryl plus other analytes have been obtained with good chromatographic integrity and sensitivity. This system routinely provided low nanogram level detection in the full scan mode for the pesticides as well as picogram levels for some selected analytes. The highest % R.S.D. for repeated injections of naphthalene over a two-week period using this benchtop SFC-EI-MS system was 6.4. The EI-mass spectra have been successfully searched using conventional mass spectral libraries. - J. Chromatogr. 633, 195 205 (1993). Dept. Chem., Geochem., School Mines, Golden, CO 80401 (USA) Automatic determination of N-methylcarbamate pesticides by using a fiquid-liquid extractor derivatization module coupled on-fine to a gas chromatograph equipped with a flame ionization detector. E. Ballesteros, M. Gallego and M. Valcfircel. To reduce human involvement in the routine analysis of carbamate pesticides a continuous extraction system for the continuous introduction of carbamate pesticide derivatives into a GLC was developed. The hydrolysis products of aryl N-methylcarbamates (phenols) were extracted with or without derivatization in a continuous fashion by using ethyl acetate or acetic anhydride in n-hexane, respectively. The acetylated phenolic portion of N-methylcarbamates is highly selective, which was taken advantage of to identify six pesticides (propoxur, carbofuran, carbaryl, aminocarb, benthiocarb and methiocarb). The chromatographic responses obtained were linear between 0.2 and 160 mg/1 of the different N-methylcarbamates, and the relative standard deviation was 1.9 - 3.9 %. - J. Chromatogr. 633, 169 - 176 (1993). Dept. Anal. Chem., Fac. Sci., Univ., Cordoba 14004 (E) Development of an enzyme-based biosensor for atrazine detection. F.A. McArdle and K.C. Persaud. An amperometric biosensor for detection of the photosynthetic inhibiting herbicide atrazine promising continuous monitoring of atrazine in aqueous environments is proposed. The sensor, incorporating the

195 enyzme tyrosinase, is sensitive to a wide range of di- and triphenols. It displayed a fast response, with 95% of the steady-state current being obtained within 25 s. Atrazine inhibition of the biosensor response was found to be reversible. The electrode construction consisted oftyrosinase cross-linked on a poly(pyrrole) coated gold electrode surface. The inhibition of enzyme activity in the presence of atrazine was measured amperometrically. Atrazine concentrations of 5 x 10- 6 tool dm-3 were measured in a hydrodynamic cell and of 1 x 10 -s tool dm -3 in a flowthrough system. In artificial seawater (pH 8.5) the sensitivity of the electrode was drastically reduced. - Analyst 118, 419-423 (1993). Dept. Instr. Anal. Sci., UMIST, Manchester, M60 1QD (GB)

Determination of fenitrothion, tetramethrin, dichlorvos, permethrin and piperonyl butoxide in insecticide formulations by liquid chromatography. J.A. Jimena Garcia, J. Gim~nez Plaza and J.M. Cano Pav6n. Mixtures of divere active components (fenitrothion, tetramethrin, dichlorvos, permethrin and piperonyl butoxide) in commercial insecticide formulations have been analyzed by liquid chromatography with good results, using spectrophotometricdetection. Variations of the retention times of the compounds with the composition of the mobile phase have been studied. The sample is dissolved in acetonitrile, injected on a LiChrosorb column, eluted with acetonitrile and detected at 240 nm. Quim. Anal. 12, 3 5 - 3 7 (1993). Dept. Anal. Chem., Fac. Sci., Univ. Mfilaga, Campus Teatinos, 29071 Malaga (E) Use of an electrode of carbon paste modified with C18 in the determination of bendiocarb. P. Hernfindez, O. Nieto, F. Galfin and L. Hern~ndez. The determination of bendiocarb using a carbon paste electrode modified with a 50% of C18 by means of differential pulse voltametry is studied. The electrode is kept for a preconcentration time of 8 min in an open circuit on the solution of the insecticide which contains BrittonRobinson buffer at pH 5. The measurements were carried out in another cell applying DPV with a AE = 70 mV and a scan rate of 30 mV s - 1 in Britton-Robinson buffer at pH 9. A limit of detection (3cy) of 0.21 lag ml-1 is obtained for the determination on soils and 0.69 lag ml-~ (10~) as limit of determinations. - Quire. Anal. 12, 18-25 (1993). Dept. Anal. Chem., Instr. Anal., Univ. Aut6n. Madrid, E-28049 Madrid (E) Enantiomer separation of synthetic pyrethroids by subcritical and supercritical fluid chromatography with chiral stationary phases. Y. Nishikawa. Enantiomers of synthetic pyrethroids can be separated by subcritical and SFC on chiral columns of the Pirkle type (like SUMI CHIRAL OA2000) with COz + 10% ethanol in hexane and hexane, respectively. Due to the temperature dependence of the separation factor low temperatures lead to better separation. Using these stationary phases, enantiomers of compounds with one or two chiral centers in acid and alcohol moieties were resolved; attempts were made to improve their resolution. The elution order of enantiomers was the same as in HPLC in the two cases studied. This technique is very promising, as it requires a shorter analysis time. - Anal. Sci. 9, 33 - 3 7 (1993). Sumitomo Chem. Co. Ltd., Environ. Health Sci. Lab., Takarazuka 665 (J) Critical evaluation of a screening test for detection of herbicides by inhibiting photosynthesis of isolated chloroplasts. G. Matuszczyk, L. Well and R. Niessner. The possibility to determine herbicides in aqueous environments by observation of inhibiting effects on the photosynthesis of isolated chloroplasts have been critically evaluated. Photosynthesis inhibiting substances, both natural and anthropogenic, can be detected collectively. That is an advantage over enzyme immunoassays which can only detect single herbicides. Clearly disadvantageous are the insufficient detection limis (e.g. 8.9 pg/l for atrazine, respectively 2.5 ~tg/1for terbuthylazine) and therefore preconcentration is needed. - Mikrochim. Acta 110, 23 30 (1993). Inst. Hydrochem., Techn. Univ. Munich, Marchioninistrasse 17, W-8000 Miinchen 70 (D) Enantiomer separation of chlordane components and metabofites using chiral high-resolution gas chromatography and detection by mass spectrometric techniques. H.R. Buser and M.D. Mtiller.

196 The chromatographic behaviour and the enantiomeric separation of chiral chlordane components and metabolites is investigated using chiral HRGC-EI and ECNI-MS and applied to the analysis of tissue extracts. Specific problems encountered with these type of analysis are described and remedies suggested. Two ~-cyclodextrin ([3-CD) derivatives were used as chiral selectors and dissolved in a polysiloxane stationary phase (PS086). Silylated [3-CD (BSCD) showed increased enantiomer resolution compared to permethylated [3-CD (PMCD); however, BSCD was less suitable for the analysis of a technical chlordane mixture. - Anal. Chem. 64, 3168-3175 (1992). Fed. Res. Station, CH-8820 W/idenswil

Determination of phenylurea pesticides in water by derivatization with heptafluorobutyric anhydride and gas chromatography-mass spectrometry. F.P.M. Karg. Eleven phenylurea herbicides were derivatized by catalytic heptafluorobutyration and cleaned-up on a silica cartridge and determined by GC on an OV-I capillary with a temperature program from 80 to 240°C. The detection was carried out by MS either in the EI or in the SIM mode. The procedure has been applied to samples of drinking water. J. Chromatogr. 634, 87 - 100 (1993). ]~coleNat. Saint~ Publ., Lab. t~tude, Rech. Environ., Sant~, F-35043 Rennes Simultaneous determination of the herbicides glyphosate, glufosinate and bialaphos and their metabolites by capillary gas chromatography]ion-trap mass spectrometry. N. Tsunoda. A selective and sensitive GC-MS method using ion trap MS as a mass detection system has been used for the determination of the herbicides glyphosate, glufosinate and bialaphos and their major metabolites. A single-step derivatization is achieved at 80°C for 30 min with the reagent N-methyl-N-(tert.-butyldimethylsilyl)trifluoroacetamide in dimethylformamide. The derivatives of three herbicides, their metabolites and nineteen amino acids were simultaneously chromatographed and well separated in a single run on a DB-I fused silica capillary column. Each tert.-butyldimethylsilylated derivative produces an easily interpretable mass spectrum dominated by unique M - 15, M - 57, M - 85 and M - 159 fragment ions. The limits of detection were estimated to be 1 0 - 20 ng for glyphosate and glufosinate and their metabolites, and 500 ng for bialaphos, by GC/IT-MS. Using GC analysis with flame ionization detection, glyphosate and glufosinate and their metabolites were detectable at levels of approximately 100 ng with the exception of bialaphos. - J. Chromatogr. 637, 167-173 (1993). Nat. Res. Inst. Police Sci., Tokyo 102 (J) Enantio-)separation of phenoxy acid herbicides using capillary zone electrophoresis (CZE). M.W.F. Nielen. CZE and cyclodextrin modified CZE has been used for the separation of structurally related phenoxy acid herbicides and the determination of impurities as positional isomers. The selectivity of the separation can be controlled and fine-tuned by using different types of cyclodextrins. The CZE method shows good precision, linearity and long-term stability. The methods developed have been successfully applied to the analysis of real samples. In comparison with chromatographic methods the CZE methods are more flexible and simpler and will be more economical and have potential for automated quality control assays. - J. Chromatogr. 637, 8 1 - 9 0 (1993). Akzo Res. Lab., Corp. Res. Anal., Environ. Chem. Dept., 6800 SB Arnhem (NL) Determination of paraquat and diquat by liquid chromatography] thermospray mass spectrometry. M. Yoshida, T. Watabiki, T. Tokiyasu and N. Ishida. LC/TSP-MS enables quantitative and qualitative analyses of paraquat and diquat without any derivatization and isolation step. HPLC was performed on a 15-cm Shim-packed CLC-ODS column, with methanolwater (80:20) + 0.1 M ammonium acetate (adjusted to pH 5 with trifluoroacetic acid) as buffers. The mass spectral sensitivity was best when the temperatures of the vaporizer, block and tip heater of the ion source block were set at 160, 310 and 320°C, respectively. When thermospray ionization was used, ions ofm/z 186 and 183 were obtained as base peaks for paraquat and diquat, respectively. Detection limits by selected ion monitoring were of the order of 20 ng (S/N = 3.5). - J.

2

Particular matrices and fields of application

Chromatogr. 628, 235-239 (1993). Dept. Legal Med., Kansai Med. Univ., 1 Fumizono-cho, Moriguchi 570 (J)

2.3

Environmental matrices

Symposium on solid-phase extraction in environmental and clinical chemistry. San Francisco, CA (USA), April 5 10 (1992). 13 Papers of this conference are now published in Journal of Chromatography. They discuss some of the various facets of sample preparation using SPE and show the importance of this rapidly expanding technology. SPE is a superior alternative to liquid-liquid extraction methods and is used throughout the isolation of compounds from complex mixtures. The extracts can often directly be used for the subsequent instrumental analysis. This is an important answer to the demand for rapid analysis of multiple samples at low costs especially for automated analysis. - J. Chromatogr. 629, 3 - 9 3 (1993). Determination of compounds in landfill gas from industrial waste by GC/ MS- and GC/MS/IR-eoupling. H. W6rmann, J. Stuth and J. Schulz. By combination of GC/IRD/MSD a valuable system for the investigation of compounds in landfill gas from industrial waste can be obtained. Retention time, mass spectrum and IR-spectrum can be used to identify more than 70 compounds. Using selected wavelength chromatography, the IRD can screen different compound classes such as ketones and siloxanes. The GC/MSD unit is used with a Petrocol DH column with a temperature program from 40°-250°C. The GC/IRD/ MSD unit uses a HP5 capillary from 60 to 200°C. - GIT Fachz. Lab. 37, 400--403 (1993). RWE Forsch. Entwickl. GmbH, W-5047 Wesseling

(D) An integrated concept of automated instrument control, quality assurance and data reporting for dioxin/furan analysis. R. Schubert, R. Pesch, H. Pfaff and E. Schroeder. A new software system is created and described for target compounds which integrates TACO (TArget COmpound analysis) as a new common user interface for QUANTUM, a new high resolution target compound analyzer. It coordinates instrument control of the high resolution mass spectrometer, the gas chromatograph and the autosampler. It takes care about data acquisition, data evaluation and quantitation according to predefined methods. These methods also determine quality control parameters from the mass spectrometer and from the data evaluation. System performance parameters can be checked against method dependent limits and may stop batch processing via feedback control. TACO finally generates reports that integrate text and graphics in a flexible user defined format. The system increases sample throughput. Chemosphere 27, 2 5 - 3 2 (1993). Finnigan MAT GmbH, W-2800 Bremen 14 (D) Experiences with mass peak profile monitoring in dioxin analysis by HRGC]HRMS-SIM. T. Takasuga, P. Ireland, T. Inoue and T. Takeda. HRGC/HRMS-SIM is used for dioxin analysis in peak top (PT) and mass peak profile (MP) mode. In the MP mode a sweep is performed over each ion detected. Using this MP method interferences seen with the standard PT method in the responses of native PeCDDs in a dirty fly ash sample, native TeCDDs in a dirty flue gas sample, and 13C12TeCDF in a dirty flue gas and fish samples, were investigated. The method enabled the responses for the interferences to be distinguished from those due to the target compounds and also enabled tentative identifications of the interfering species. - Chemosphere 27, 3 3 - 4 0 (1993). Shimadzu Techno-Research Inc., Shimadzu Corp., Kyoto 604

(J) Fourier transform infrared spectrometric analysis for particle-associated ammonium sulfate. K.J. Krost and W.A. McClenny. The applicability of FT-IR transmission spectrometry to the quantitative determination of ammonium sulfate has been demonstrated. The

2.3

Environmental matrices

integrated absorbance (635 to 595 cm 1) due to sulfate were measured in ambient particulate matter collected onto Teflon filters. The detection limit for ammonium sulfate is 1.2 gg/cm 2, which corresponds to 0.36 gg/m 3 sampled over 24 hours at 15.0 1/min for ammonium sulfate. The results were compared to those obtained with XRF and ion chromatography. Appl. Spectrosc. 46, 1737-1740 (1992). Atmospheric Res., Exposure Assessment Lab., U.S. Environ. Protect. Agency, Research Triangle Park, NC 27711 (USA)

Semiquantitative analysis of environmental materials by laser-sampling inductively coupled plasma mass spectrometry (LS-ICP-MS). E.R. Denoyer. LS-ICP-MS has been found to be useful for the semiquantitative analysis of solid environmental samples. Particulate samples are mixed with a cellulose-based binding agent and pressed into pellets for direct solid sampling by the laser. Semiquantitative analysis results are typically accurate to within 2 0 - 4 0 % using internal standardization and within a factor of 2 - 3 without internal standardization. Precision is typically better than 15% relative standard deviation. Detection limits were limited by the purity of the binding material used to produce the pellet and typically ranged between 0.002 and 1.0 ~tg g 1. Due to their relatively high spectral backgrounds in ICP-MS K, Ca, Mg, Si, P and S are difficult to determine. - J. Anal. At. Spectrom. 7, 1187-1193 (1992). PerkinElmer Corp., Norwalk, CT 06859 (USA) Determination of environmental contaminants using an electrospray interface combined with an ion trap mass spectrometer (ITMS). H.Y. Lin and R.D. Voyksner. The determination of environmental contaminants using a commercial electrospray interfaced to an ITMS is described. The system was optimized to achieve maximum sensitivity. Ions were injected into the trap, which was held at a helium pressure of 3 x 10 4 Torr, at a qz value of 0.1-0.15. Collisional activation of ions generated from pesticides and dyes was achieved in the electrospray transport region by adjusting the repeller voltage. The ion trap was also used to provide structural information about the [M + H] + ions formed. Collisional activation in the electrospray transport region required high sample purity. The MS/ MS spectra generated in the ITMS were less susceptible to interference from matrix components. Liquid chromatography/electrospray-ITMS was used to analyze a spiked water sample directly. Full-scan electrospray CID spectra were obtained on 10-30 pg quantities of material, resulting in low ppb detection. - Anal. Chem. 65, 451-456 (1993). Anal. Chem. Sci., Research Triangle Inst., Research Triangle Park, NC 27709 (USA) Application of boron isotopes for identifying contaminants such as fly ash leachate in groundwater. G.R. Davidson and R.L. Bassett. To determine the ratio of B isotopes in a fly ash leachate and that of groundwater, groundwater samples have to be concentrated on an ionexchange resin before methylborate destillation. The dry residues of the destillates were analyzed with a thermal ionization mass spectrometer (1 aBO 2 -/lOBO 2- at amu 43 and 42, respectively). Mixtures of leachate and groundwater typically result in nonlinear B isotope mixing curves that enable identification and quantification of leachate contamination in a groundwater at much lower levels than possible using concentration analyses alone. - Environ. Sci. Technol. 27, 172--176 (1993). Dept. Hydrology, Water Resources, Univ., Tucson, AR 85721 (USA) Characterization of environmental dusts by X-ray fluorescence spectrometry using a micro bead presentation. L.V. Moore. Small dust samples of mass ca. 0.07 g are fused with a lithium fluoridelithium tetraborate flux to yield a homogeneous micro bead. These beads are presented to a wavelength-dispersive spectrometer and the composition of the sample derived from calibration effected with internal standards. Matrix corrections are calculated by an NBSGSC algorithm. The method can be used for the characterization of various'dusts dispersed around cement factories. - X-Ray Spectrom. 22, 2 8 - 32 (1993). Techn. Serv. Dept., Pretoria Portland Cement Co., Cleveland 2022 (ZA) Differentiation between organic and inorganic chlorine by electrothermal vaporization inductively coupled plasma mass spectrometry: Application

197 to the determination of polychlorinated biphenyls in waste oils. P. Richner and S. Wunderli. ICP-MS can be used as a screening test for chlorinated organic compounds such as PCBs in oils. To differentiate between 'organic' chlorine (PCB-chlorine) and inorganic chlorine electrothermal vaporization ICPMS using a temperature programme having one step at 400°C, for the vaporization of the PCBs, and a second at 2650 °C, for the vaporization of the inorganic chlorine compounds, is used. The detection limits are between 0.5 and 10 gg of PCB per gram of oil depending on the nature of the oil and the degree of chlorination of the PCB. J. Anal. At. Spectrom. 8, 4 5 - 4 9 (1993). Swiss Fed. Lab. Mat. Test. Res., CH-8600 Dfibendorf (CH) Anion exchange for the eliminasation of spectral interferences caused by chlorine and sulfur in inductively coupled plasma mass spectrometry. J. Goossens and R. Dams. Spectral interference on V, Cr, Cu, Zn, As and Se caused by C1 and S in ICP-MS during the analysis of biological, clinical and environmental samples can be overcome by separation on a Dowex-1 column in the NO3 -form. The analytes were eluted with diluted nitric acid and collected in the eluate. In most of the examples, the sample preparation is limited to a reduction with SnCI2. This new approach to the elimination of spectral interferences has been applied to soils, percolate water, sewage and human serum. The results are in good agreement with certified values and results obtained by d.c. plasma atomic emission spectrometry and electrothermal vaporization atomic absorption spectrometry; differences between mean values are < 5%. Sample volumes of 50 ml are used. -- J. Anal. At. Spectrom. 7, i167-1171 (1992). Lab. Anal. Chem., Inst. NucI. Sci., Univ., B-9000 Gent Fourth order derivative spectrophotometric determination of lead with 1,10-phenanthroline and rose bengal. D. Sreevalsan Nair, T. Prasada Rao, C.S.P. Iyer and A.D. Damodaran. A fourth order derivative spectrophotometric procedure for the determination of traces of lead based on the liquid-liquid extraction of ternary ion association complex of lead with 1,10-phenanthroline and rose bengal into chloroform is described. The ternary ion associate is stable for over 24 h. The developed procedure is simple, rapid, reliable and allows the determination of as low as 20 ppb of lead in sea water samples. - Anal. Lett. 26, 523-539 (1993). Reg. Res. Lab. (CSIR), Trivandrum 695 019 (IND) Effects of temperature and pressure on supercritical fluid extraction efficiencies of polycyclic aromatic hydrocarbons and polychlorinated biphenyls. J.J. Langenfeld, S.B. Hawthorne, D.J. Miller and J. Pawliszyn. Three CRMs, polychlorinated biphenyls (PCBs) from river sediment, polycyclic aromatic hydrocarbons (PAHs) from urban air particulate matter, and PAHs from highly contaminated soil, were extracted with pure C O 2 at conventional (50°C) and high (200°C) temperatures. Raising the extraction temperatures greatly increases SFE recoveries, while raising the extraction pressure from 350 to 650 atm has no effect on extraction efficiencies at 50°C. Increasing SFE temperatures may be a useful alternative to adding organic modifiers for achieving high extraction efficiencies from environmental samples. - Anal. Chem. 65, 338-344 (1993). Univ. North Dakota, Energ. and Envir. Res. Cent., Grand Forks, ND 58202 (USA) Simultaneous determination of alkali, alkaline-earth metal cations and ammonium in environmental samples by gradient ion chromatography. E. Dabek-Zlotorzynska and J.F. Dlouhy. A fully automated system for the suppressed gradient IC separation of Li ÷, Na + , NH4 +, K +, Rb + , Cs +, Mg 2+ , Ca 2+ and Sr 2÷ is presented to determine these cations in water extracts of ambient air particulates collected on thin PTFE filters. The procedure is also potentially available for any aqueous samples. - J. Chromatogr. 638, 35-41 (1993). Chem. Div., River Road Environ. Technol. Cent., Ottawa, Ontario K1A 0H3 (CON) Differentiation of aroclors using linear discrimination for environmental samples analyzed by electron capture negative ion chemical ionization mass spectrometry (ECNICI-MS). Cheng Yu Ma and C.K. Bayne.

198 The advantages of ECNICI-MS coupled with sequential classification methods are investigated using linear discrimination to determine the total PCB content in an environmental sample by using one of the Aroclor standards as calibration standard. Eight Aroclors (i.e., 1016, 1232, 1242, 1248, 1254, 1260, 1262, and 1268)were analyzed by ECNICI for a range of concentration levels. Using selective ion display, the ion abundances of the prominent peaks in the isotopic clusters of molecular ions were measured for eight PCB homologs (C12- C19) within their GC retention time windows for each sample. Corresponding relative ion abundances from eight Aroclor standards were used as classification training sets. These training sets were used to develop a classification algorithm. This technique employed a sequential application of two sets of linear discriminant functions to successfully identify known EPA quality control and environmental samples. - Anal. Chem. 65, 7 7 2 777 (1993). Anal. Chem. Div., Compl. Appl. Div., Oak Ridge Nat. Lab., Oak Ridge, TN-37831 (USA) Determination of mono- and non-o,o'-chlorine substituted polychlorinated biphenyls in Aroclors and environmental samples. T.R. Schwartz, D.E. Tillitt, K.P. Feltz and P.H. Peterman. A method is presented that uses dispersed carbon on glass fibers and commercially available instrumentation to fractionate and determine mono- and non-o,o'-chlorine substituted PCB congeners in Aroclors and environmental samples. - Chemosphere 26, 1443-1460 (1993). U.S. Fish Wildlife Serv., NFCRC, Columbia, MO 65201 (USA) Magnetic particle based enzyme immunoassay as a rapid screening method for the analysis of atrazine in environmental samples. A. Dankwardt, J. Seifert and B. Hock. A very quick and simple screening of atrazine in environmental samples can be achieved using a magnetic particle based enzyme immunoassay working between 0.04 and 5 ppb. Coefficients of variation below 10% were achieved. Soil and water samples were analyzed, the latter ones without clean-up. No interferences of the sample matrices could be found. Comparison of atrazine concentrations determined by the magnetic particle based assay, a microtitre plate assay, and GC showed good correlations. - Acta hydrochim, hydrobiol. 21, I 10-113 (1993). Techn. Univ. Miinchen-Weihenstephan, Lehrst. Botanik, W-8050 Freising 12 (D) Determination of pesticides by HPLC. C. Schlett. An overview is given for using SPE/HPLC for the determination of various pesticides of different chemical structure, thermolabile or polar components included, in a single run. Due to longer elution times compared to gas chromatography, only a limited number of components can be determined at the same time. All components relevant for a water catchment area can be covered. With the use of diode-array-detectors the identification of components can be done with sufficient security by comparison of spectra of reference sample and analytical peak. The determination limit is 0.025 gg/1 with few exceptions. 21 References. Acta hydrochim, hydrobiol. 21, 102-109 (1993). Gelsenwasser AG, Abt. Wasserchem., Postfach 100 944, W-4650 Gelsenkirchen (D) Field detection of organochlorine pesticides by thermal desorption gas chromatography/mass spectrometry (TDGC/MS). A. Robbat, Jr., Chengjie Liu and Tyng-Yun Liu. For the field detection of organochlorine pesticides in soil/sediment and water a TDGC/MS unit with a DB-5 film capillary and a temperature program from 120 to 240°C was proposed. Rapid (3 rain/sample) TDGC/MS selected ion monitoring (SIM) yielded detection limits of 50 ng/g and 40 ng/1 pesticide in soil (2 g) and water 500 ml), respectively, with measurement precision < 40%, MS total ion current-selected ion extraction (TIC-SIE) measurements yielded somewhat higher detection limits with measurement precision <20%. Examples of selective pesticide detection in the presence of a wide variety of environmental contaminants in soils, pond and sea waters are provided. - J. Chromatogr. 625, 277-288 (1992). Trace Anal. Measurement Lab., Dept. Chem., Tufts Univ., Medford, MA 02155 (USA) Use of extraction disks for trace enrichment of various pesticides from river water and simulated seawater samples followed by liquid chromatography-

2

Particular matrices and fields of application

rapid-scanning UV-visible and thermospray-mass spectrometry detection. D. Barce16, G. Durand, V. Bouvot and M. Nielen. For extracting polar pesticides from water samples SPE with Empore extraction is tested. C18 Empore extraction disks were used for the isolation and trace enrichment of several pesticides [chlorotriazines (atrazine, simazine and cyanazine), the atrazine metabolites (deethyland deisopropytatrazine), organophosphorus (parathion-ethyl, fenitrothion, fenamiphos, and tetrachlorvinphos), phenylnrea (linuron), propioanilide (propanil), and carbamate (carbaryl)] from river water and simulated seawater, at concentration levels of 0.25, 25, and 1000 gg/1. The extraction disks allowed relatively high flow rates; thus 1- (for 1000 Ixg/1) and 4-1 (for 25 and 0.25 gg/1) samples could be processed within 30 and 120 rain, respectively. For most of the pesticides the recoveries varied from 80 to 125 % whereas for the atrazine metabolites the recoveries varied from 3 to 17%. The limits of detection (LOD) were 0 . 0 2 0.01 gg/l. Thermospray liquid chromatography-mass spectrometry in the positive and negative ion modes and filament on has been used for the unequivocal identification of various pesticides following solid-phase extraction. The LOD varied between 2 and 20 gg/1. - Environ. Sci. Technol. 27, 271-277 (1993). Environ. Chem. Dept., CID-CSIC, 08034 Barcelona (E) Determination of coplanar polychlorobiphenyl congeners in biota samples. M.D. Pastor, J. Sanchez, D. Barcel6 and J. Albaig~s. Separation of coplanar congeners of polychlorobiphenyls (PCBs) (IUPAC Nos. 81, 77, 126 and 169) from other organic micropollutants such as hydrocarbons, organochlorinated pesticides and other PCBs is possible with a two-step clean-up procedure with sulphuric acid and LC fractionation (Hypercarb column). The separation of the coplanar PCBs in the Hypercarb column requires only 100 ml of n-hexane. Recoveries ranged from 84 to 97% for these and sixteen other PCB congeners. GC/ ECD of all the compounds was performed using capillary GC columns of different polarity, CP-Sil-8 CB or DB-5, DB-17 or DB-225, followed by confirmation by GC-MS in the electron impact and selected ion monitoring mode. The whole analytical method permits the determination of individual PCBs in biota samples at a level of 1 ng/g wet tissue. - J. Chromatogr. 629, 329-337 (1993). Environ. Chem. Dept., CID-CSIC, 08034 Barcelona (E) Determination of a trace amount of beryllium in water samples by graphite furnace atomic absorption spectrometry after preconcentrafion and separation as a beryllium-acetylacetonate complex on activated carbon. T. Okutani, Y. Tsuruta and A. Sakuragawa. A method is described which can determine ~ 10 12 g Be in natural water. It is based on a rapid step ofpreconcentration by selective adsorption using activated carbon as an adsorbent and acetylacetone as complexing agent at pH 8 - 1 0 . The activated carbon which adsorbed the beryllium-acetylacetonate complex was separated and dispersed in pure water. The resulting suspension was introduced directly into the graphite furnace atomizer. The determination limit was 0.6 ng/1 (S/N= 3), and the relative standard deviation at 0.25 gg/1 was 3.0-4.0% ( n = 6). Not only was there no interference from the major ions such as Na(I), K(I), Mg(II), Ca(II), CI-, and SO42- in seawater but there was also no interference from other minor ions. - Anal. Chem. 65, 1273-1276 (1993). Dept. Ind. Chem., Coll. Sci. Technol., Nibon Univ., Chiyodaku, Tokyo 101 (J) Determination of arsenic(V) and arsenic(III) species in environmental samples by copreeipitation with zirconium hydroxide and pre-atomization atomic absorption spectrometry. Chen Yalei, Qi Wenqi, Cao Jieshan and Chang Mou-sen. To determine ultra-trace amounts of arsenic species in environmental samples, the As species are coprecipitated with zirconium hydroxide and subsequently a pre-atomization of AsC13 was carried out. By means of different temperature programmes, arsenic(III) can quantitatively be removed from a graphite tube coated with zirconium, while arsenic(V) quantitatively remains in the furnace up to a temperature of 1400°C. The recoveries from environmental samples are satisfactory. - J. Anal. At. Spectrom. 8, 3 7 9 - 381 (1993). Nat. Environ. Monit. Cent., Beiyuan, Beijing 100012 (RC)

2.3

Environmental matrices

Determination of mercury in industrial workplaces by collection on activated carbon, solvent extraction and cold-vapour atomic absorption spectrometry. E. Garcia Sanchez, M. Hernandez Lopez and A. Arbaizar Ruiz de Dulanto. A method for the determination of mercury in workplace environments in a chlor-alkali plant was optimized. Mercury was collected on activated carbon with a personal sampling pump at a flow-rate of 0.5 1/ min, then the carbon was mineralized by heating with potassium permanganate and sulphuric acid. The mercuric ion was chelated with ammonium pyrrolidinedithiocarbamate and extracted with methyl isobutyl ketone at acidic pH (1.6-5). The chelate in the extract was decomposed with sulphuric acid and the mercuric ion reduced to the metal with stannous chloride. The mercury was determined by coldvapour atomic absorption spectrometry (CVAAS). The calibration graph was linear up to 5 ng/ml Hg in the initial solution, the relative standard deviation was 4.5% (for 2 ng/ml) and the detection limit was 0.14 ng/ml. The proposed method is in good accordance with CVAAS without extraction. - Mikrochim. Acta 110, 167-172 (1993). Dept. Anal. Chem., Fac. Sci., E-29071 Mfilaga (E) Solid-phase extraction procedure for the determination of selenium by capillary gas chromatography. K. Johansson, U. (~rnemark and A. Olin. An SPE method in trace analysis of Se(IV) in water with GC/ECD is reported. After derivatization of Se(IV) with 1,2-diamino-3,5dibromobenzene the formed 4,6-dibromopiazselenol was adsorbed on a porous divinylbenzene polymer. Elution was performed with toluene. The proposed solid-phase extraction procedure was compared with a liquid-liquid extraction procedure and the overall efficiency was approximately 97% for sample volumes between 5 and 100 ml. The GC separation was performed on a DB-1701 film capillary with a temperature program from 100-265°C. Concordant results were obtained for natural water samples spiked with selenium between the GC-ECD procedure and a hydride generation atomic absorption spectrometric procedure. Dissolved organic carbon can be removed from water with XAD-8 and Dowex 1X8. -- Anal. Chim. Acta 274, 129-140 (1993). Dept. Anal. Chem., Univ., S-75121 Uppsala Determination of airborne cadmium in environmental tobacco smoke by instrumental neutron activation analysis with a Compton suppression system. S. Landsberger, S. Larson and D. Wu. The toxic Cd steming from tobacco smoke can be determined in indoor air by NAA. Particulate-phase cadmium concentrations on air filter samples were detected by epithermal instrumental NAA in conjunction with a Compton suppression y-ray detection system, in which the detection limit for cadmium was reduced to a few nanogram per filter. A cascade impactor and a personal filter sampler were used to collect the indoor suspended particulate matter for size-fractionated mass as well as total mass, respectively. - Anal. Chem. 65, 1506-1509 (1993). Dept. Nucl. Engin., Univ., 214 Nucl. Engin. Lab., Urbana, IL 61801 (USA) HPLC fluorescence determination of nitrites in water using precolumn derivatization with 4-methyl-7-aminocoumarin. J.Y. Zhou, P. Prognon, C. Dauphin and M. Hamon. A rapid, simple, and sensitive method is described for determination of nitrites in water. Nitrite ions react with 4-methyl-7-aminocoumarin in sulfuric acid medium to give the corresponding 7-diazo-compound. After hydrolysis, this latter yields (95%) the highly fluorescent 4-methyl7-hydroxycoumarin (4-methylumbelliferone) which is fluorimetrically detected at 380 nm after excitation at 325 nm. To avoid interferences an HPLC separation is obtained on a cyano stationary phase with hexaneisopropanol (95:5, v/v) as eluent. Under these conditions, linearity of response is obtained from J to 30 gg/1 of NO2- ; the limit of detection is 0.5 gg/1. The repeatability and reproducibility, expressed as RSD %, are 2.5 and 4.7% respectively, for n = 6 and 5 gg/1. - Chromatographia 36, 5 7 - 6 0 (1993). Lab. China. Anal. II, Fac. Pharm., F-92290 ChatenayMalabry (F) Determination of carbonyl sulfide and hydrogen sulfide species in natural waters using specialized collection procedures and gas chromatography with flame photometric detection. J. Radford-Knoery and G.A. Cutter.

199 Sampling procedures and analytical techniques for the simultaneous determination of total dissolved sulfide (H2S,q + HS- + S2- + complexed sulfide) and organic sulfide (OCS) (dimethylsulfoxide + carbonylsulfide) in natural waters are investigated. The analytical method is based on stripping an acidified 1 - 300 ml sample with helium, liquid nitrogen-cooled trapping of the evolved gases, followed by gas chromatographic separation and flame photometric detection. To eliminate artifacts, determinations are made in the field immediately after sample collection. Detection limits are 0.2 pmol/1 for total dissolved sulfide and 1.3 pmol/1 for OCS. Precision is better than 5% (relative standard deviation) for both sulfur compounds at the 50 pmol/1 level. In combination with selective chemical treatments, the method can also be applied to the determination of acid-volatile sulfide and chromiumreducible sulfur in suspended particles. - Anal. Chem. 65, 976-982 (1993). Dept. Oceanogr., Old Dominion Univ., Norfolk, VA 23529-0276 (USA) Measurement of ambient ozone using a nitrite-coated filter. P. Koutrakis, J.M. Wolfson, A. Bunyaviroch, S.E. Froehlich, K. Hirano and J.D. Mulik. Ozone can be monitored by using a coated filter for ozone collection. The passive ozone sampler consists of a badge clip supporting a barrelshaped body which contains two coated glass fiber filters. The principal component of the coating is nitrite ion, which in the presence of ozone is oxidized to nitrate ion on the filter medium, NO2- + 03 ~ NOa+ Oz. After sample collection, the filters are extracted with ultrapure water and analyzed for nitrate ion by ion chromatography. The results from laboratory and field validation tests indicate excellent agreement between the passive method and standard ozone monitoring techniques. - Anal. Chem. 65, 209-214 (1993). Dept. Environ. Health, Harvard School Publ. Health, Boston, MA 02115 (USA) Atmospheric methane: sources, sinks and role in global change. Proceedings of the NATO Advanced Research Workshop. Timberline Lodge on Mount Hood in Oregon (USA), 7-11 October 1991. Methane, an integral component of global atmospheric chemistry, contributes besides carbon dioxide to the future global warming. The NATO advanced workshop was organized to present a collection of papers describing the latest research on atmospheric methane. Nearly 100 scientists from 19 countries presented their latest research on this issue. A part of these contributions as well as invited papers are published in a special issue of Chemosphere. The papers deal with the measurement and research techniques, mass balance issues, sources (plants, animals, soil, industrial), sinks and the environmental role of methane and future trends. - Chemosphere 26, No. 1 - 4 (1993). Continuous measurements of emissions of gaseous components. Experience gained in lignite-coal power plant. S. Biniaris, J. Hildebrandt and A. Piolot. The concept of continuous measurement of emissions for gaseous components in a lignite-coal power plant is described. When determining the separation efficiency of a final cleaning installation and the degree of emission, concentration measurements of flue-gas components are also required downstream the final waste gas cleaning installation. In case a boiler has two waste-gas flues, then a "bypass" system can be used so that the emission concentration of the flues can be measured with a single set of measurement instruments. In addition, based on the experience gathered with the extractive and with the "in situ" measurement technique, an attempt is made to describe the advantages and disadvantages of these two measurement methods. - Staub - Reinhaltung Luft 53, 4 3 - 46 (1993). Method for the determination of some soluble atmospheric carbonyl compounds. Yin-Nan Lee and Xianilang Zhou. Soluble atmospheric carbonyl compounds are determined using a pyrex coil gas-liquid scrubber sampler in conjunction with HPLC equipped with a UV-visible detector for separation and identification following derivatization with 2,4-dinitrophenylhydrazine (DNPH). Carbonyls like formaldehyde (FA), glycolaldehyde (GA), glyoxal (GL), and methyiglyoxal (MG) can be measured. The limits of detection are ~ 0.005

200 ppb (in the gas phase) for MG, ~0.01 ppb for GL, and ~0.02 ppb for FA and GA. Interferences from aqueous-phase reactions of 03 are insignificant. - Environ. Sci. Technol. 27, 7 4 9 - 756 (1993). Dept. Appl. Sci., Environ. Chem. Div., Brookhaven Nat. Lab., Upton, New York 11973 (USA) Development and comparison of different fluorimetric HPLC-methods with standard methods for the determination of formaldehyde in the atmosphere. A.H.J. Gr6mping and K. Cammann. Three different fluorimetric methods for the measurement of atmospheric formaldehyde are compared. The 2-diphenylacetylindan1,3-dionhydrazine method was developed and optimized with an improved limit of detection of 2 ppbv corresponding to a sample volume of 7.5 1. Separation of lutidines necessary for the Nash method was successfully carried out and the separation time was reduced by a factor of 5. The detection limit of the Nash method was improved to 1 ppbv. In comparison, the N,N-diphenyl-l-naphthylamine-5-sulfonhydrazine method performed in a similar manner, reached an LOD of 0.5 ppbv. The methods were tested for candle smoke. - Chromatographia 35, 142-148 (1993). Anal. Chem., Anorg. Chem. Inst., Univ., W-4400 Miinster (D) Comparison of two sampling methods for determining formaldehyde concentrations in workplace air. D. Kuchenbecker, H. Grau und H. Schaffernicht. Two sampling methods for formaldehyde were tested simultaneously under laboratory and workplace conditions in the institute for pathology of the University Leipzig. The first method (DFG-method) makes use of a silicagel tube to collect formaldehyde from the air. The second method (TGL-standard) consists in separating the water-soluble formaldehyde from the contaminated air. On account of the fact that the degree of desorption of formaldehyde from silicagel is 0.96, it can be stated that the formaldehyde concentrations determined by means of the two sampling methods are equivalent. The analysis of formaldehyde adsorbed on silicagel is more time consuming. - Staub - Reinhaltung Luft 53, 143-145 (1993). Preconcentration and separation of some organic water pollutants with polyurethane foam and activated carbon. M.S. E1-Shahawi. Pesticides and phenols can be extracted from water by adsorption on untreated polyurethane foam and activated carbon. The adsorption of the compounds was brought about by a mechanism similar to that of solvent extraction. The effect of various experimental conditions such as temperature, extracting medium, pH, contact time, volume of sample flow rate, compound concentration, and eluting solvents on the retention and separation of the compounds has been determined. The height equivalent to a theoretical plate (HETP) was calculated from breakthrough capacity curves and from chromatograms obtained from polyurethane foam columns for the insecticide. Extraction of the compounds from natural water, and subsequent recovery, were both found to be complete. The high capacity of polyurethane provides advantages over activated carbon; in particular, large sample volumes can be analyzed at high flow rates. - Chromatographia 36, 318-322 (1993). Chem. Dept., Fac. Sci., U.A.E. Univ., A1-Ain (United Arab Emirates) Assessment by gas chromatography-mass spectrometry of hexenes emitted to air from petrol. O. Ramn~s, U. Ostermark and G. Petersson. Hexenes and cyclohexenes in vapours of conventional petrol can be separated by GC on an AlzO3 + 5% KC1 column. All hexenes appear in a favourable chromatographic position between hexanes and heptanes. The seventeen isomeric acyclic hexenes were identified by mass spectra and single-ion monitoring on an ion-trap mass spectrometer. J. Chromatogr. 638, 65 - 69 (1993). Dept. Chem. Environ. Sci., Chalmers Univ. Technol., 41296 Gothenburg (S) Determination of polyacrylate super absorbent polymers in air. S.P. Tucker, M.B. Millson and D. D. Dollberg. For sampling a starch-grafted, cross-linked sodium polyacrylate in air and several other polyacrylate super absorbent polymers a 37-mm PVC membrane filter is used, followed by treatment of the sample with 0.07 M

2

Particular matrices and fields of application

cupric acetate solution to form a copper-polymer precipitate, digestion of the precipitate with nitric and perchloric acids, and measurement of the copper content by ICP-AES by means of a calibration curve. This analytical method has been compared with a sodium method that currently is used. Detection limits for various super absorbent polymers ranged from 4.4 to 14 micrograms per sample. - Anal. Lett. 26, 9 6 5 980 (1993). Dept. Health and Human Serv., Nat. Inst. Occup. Safety and Health, Div. Phys. Sci., Engin., Cincinnati, OH 45226 (USA) On-line method for the analysis of sea-water for trace dements by inductively coupled plasma mass spectrometry. Plenary lecture. J.W. McLaren, J.W.H. Lain, S.S. Berman, K. Akatsuka and M.A. Azeredo. The commercially available chelation concentration system (Dionex IC/ICP) for the on-line preconcentration of trace metals from saline solutions was modified to permit the simultaneous determination of Fe, Mn, Co, Ni, Cu, Zn, Cd and Pb in sea-water samples in less than 10 rain by ICP-MS. The system was operated both with columns provided by the manufacturer and with columns containing silica-immobilized 8hydroxyquinoline. Detection limits in sea-water ranged from 1.6 ng 1 (for Pb) to 55 ng 1-1 (for Ni) for the former columns, and from 0.3 ng 1- 1 (for Cd) to 47 ng 1-1 (for Fe) for the latter. - J. Anal. At. Spectrom. 8, 279-286 (1993). Inst. Environm. Chem., Nat. Res. Council, Ottawa, K1A 0R6 (CDN) Determination of trace amounts of aluminium in natural waters by solidphase spectrofluorimetry. J.L. Vilchez, A. Navai6n, R. Avidad, T. Garcia-L6pez and L.F. Capitfin-Vallvey. A solid phase methodology with higher sensitivity, lower detection limits and lower interferences than in solutions is developed for the determination of trace amounts of aluminium. Aluminium reacted with salicylidene-o-aminophenol to form a fluorescent complex that was adsorbed on a dextran-type cation-exchange gel. The fluorescence of the gel, packed in a 1 mm silica cell, was measured directly with use of a solid-surface attachment. The applicable concentration range was flom 0.20 to 14.00 gg 1-1, with a relative standard deviation of 1.0% and a detection limit of 0.02 gg 1- 2. The method was applied to the determination of aluminium in natural waters. - Analyst 118, 3 0 3 - 307 (1993). Dept. Anal. Chem., Univ. Granada, E-18071 Granada (E) Determination of tin in natural waters and fruit juices by solid phase spectrophotometry. M.C. Valencia, D. Gimeno and L.F. CapitanVallvey. Tin reacts with Pyrocatechol Violet at pH 3 to form a 2:1 (PVC: Sn) complex which is fixed on a dextran type anion-exchange gel. The gel phase absorbance is measured directly at 576 and 800 nm for both sample and blank, and allows for the determination of tin in the range of 0.8 - 15.0 gg 1-1, with an RSD of 4.3%. The method has been applied to the determination of Sn(IV) in natural and sea waters and pineapple juice. - Anal. Lett. 26, 1211 1226 (1993). Dept. Anal. Chem., Fac. Sci., 18071 Granada (E) Automated determination of iron in seawater by chelating resin concentration and chemiluminescence (CL) detection. H. Obata, H. Karatani and E. Nakayama. To determine Fe(III) in sea water Fe(III) in an acidified sample solution is selectively collected on 8-quinolinol immobilized chelating resin and then eluted with dilute HC1. The resulting eluent is mixed with luminol solution, aqueous ammonia, and hydrogen peroxide solution successively, and then the mixture is introduced into the CL cell. The iron concentration is obtained from CL intensity. The detection limit of iron(III) is 0.05 nmol 1-1 when using an 18 ml sea water sample. Anal. Chem. 65, 1524-1528 (1993). Dept. Chem., Fac. Sci., Univ., Kyoto 606-01 (J) Determination of lead in seawater by inductively coupled plasma atomic emission spectrometry combined with chelating resin preconcentration and hydride generation. R.A. Reimer and A. Miyazaki. The combination of the preconcentration on Chelex-100 can be applied to the determination of ng/1 levels of Pb in seawater. The detection limit of the proposed method was 6 ng 1-1, which was about 100 times

2.3

Environmental matrices

better than the methods using preconcentration such as solvent extraction or ion exchange, followed by ICP-AES with direct nebulization of the solution. The method was checked with a reference material. - J. Anal. At. Spectrom. 7, 1239-1242 (1992). Nat. Inst. Resourc. Environ., Tsukuba, Ibaraki 305 (J) Spectrophotometric determination of selenium in industrial waste water using 1,2-diaminobenzene derivatives after preliminary extraction of Se(IV). B. Kasterka. A method for the determination of total selenium in waste water of the chemical industry is presented. The method is based on the reaction of Se(IV) with 4-chloro-l,2-diarninobenzene or its derivative N'-(2'hydroxypropyl)-l,2-diamine-4-chlorobenzene (PC1DAB). PC1DAB is advantageous for serial analysis because of its short reaction time with Se(IV). The absorbance of the Se-PCIDAB complex is measured at 352 nm. Organic pollutions in wastes samples were mineralized by the mixture of H2SO4, HNO3 and HCIO4. Se(IV) was separated by selective extraction of SeBr4 into CC14 from the solution containing H2SO4 and KBr. The content of selenium in averaged wastes was from 51 ng m l to 236 ng ml -~. - Chem. Analit. 37, 361--367 (1992). Inst. Inorg. Chem., Technol. Corrosion, Techn. Univ., 80-952 Gdafisk (PL) Simultaneous determination of antimony, arsenic and selenium in natural waters by means of hydride generation coupled to plasma source mass spectrometry. C. Haraldsson, M. Pollak and P. Ohman. As, Sb and Se can be determined simultaneously in natural waters by a hydride generation batch technique. To the acidified sample Na4BH4 is added and the resulting hydrides were transported from the sample to the plasma by the nebulizer gas flow. Ammonium pyrrolidin-l-yldithioformate has to be replaced by iodide to reduce Sb, I interfers in the hydrid generation of selenium. The detection limits for a 10 ml sample (S/N=3) were 1.5 ng 1 1 for arsenic, 2.4 ng 1-1 for antimony and 6.3 ng 1-1 for selenium. The precision for each element was better than 6%. The linear ranges of the method were checked for arsenic, antimony and selenium up to 2 pg 1-1, but for arsenic and antimony these were significantly higher, with the carryover between the samples being the limiting factor at high concentrations. The total analysis time for a single sample was 10 rain. - J. Anal. At. Spectrom. 7, 1183-1186 (1992). Dept. Anal. Marine Chem., Univ., S-41296 G6teborg Fluorimetric determination of cadmium traces with Brilliant Green. Applications to potable and sea waters. V. Kabasakalis and R. Tsitouridou. A simple and rapid fluorimetric determination of Cd 2 + based on its reaction with iodide and Brilliant Green is described. This reaction gives an ion-association fluorescent complex between CdI42- and Brilliant Green cation (256 nm/521 nm). The optimum pH value for complex formation is 3.0, the optimum concentration of Brilliant Green 15 rag/1 and the optimum concentration of KI 200 rag/1. Cd can be determined in the range from 5 - 100 ltg/i, the method is applied to potable and sea water. The detection limit was 1.04 ~tg/l (3c~). - Fresenius Envir. Bull. 1 , 4 9 4 - 4 9 8 (1992). Lab. Anal. Chem., Chem. Engin. Dept., Aristotelian Univ., 54006 Thessaloniki (GR) Anion-exchange preconcentration-spectrophotometric determination of traces of copper in natural water samples. T. Kiriyama. A preconcentration-spectrophotometric determination of copper in sea and fresh water samples is described. After the sample is treated with permanganate, copper is allowed to enrich on a strongly basic anionexchange column (Amberlite CG 400 in the chloride form; d? 1.0 x 4.5 cm) from 2 1 of acidified, heated sample water (40°C, 0.01 M in HC1) in the presence of 0.01 M ascorbic acid. To enhance the adsorption the fresh water is made saline before sorption by adding sodium chloride to yield ca. 0.5 M concentration. Copper sorbed on the column can be stripped by elution with 20 ml of 1 M nitric acid. Copper is then determined spectrophotometrically with diethyldithiocarbamate. This combined method is sensitive to as low as 2 x 10 -~° M of copper in 2 1 sample. Cadmium, nickel, manganese(II), lead, zinc, iron(III), cobalt, mercury(II) and silver do not interfere in the presence of even 100 times as much as their contents in seawater samples. The precision (RSD) of 3 ~ 7 % at a copper level of 0.4~0.8 gg/l can be obtained. - Bunseki

201 Kagaku 42, 2 2 3 - 2 2 8 (1993); (Orig. Jap.) Chem. Lab., Fac. Educ., Kagoshima Univ., Kagoshima 890 (J) Preconcentration of chromium, copper and manganese from sea water on pretreated solid materials for determination by atomic absorption spectrometry. F. Ball], A.M. Cardinale and R. Bruzzone. A comparison between Chelex-100 and Lewatit TP 207 resins showed that the macroporous Lewatit TP 207 is able to recover both the colloidal form and the free dissolved ionic form of Cr(III). For Cu(II) the use of both exchangers on two sea water subsamples will give useful information, whereas for Mn(II) the choice of Chelex-100 or Lewatit TP 207 is immaterial. Anal. Chim. Acta 270, 7 9 - 86 (1992). Ist. Chim. Gen., Cattedra Chim. Anal., Univ., 16132 Genova (I) Direct determination of cadmium in sea-water by electrothermal atomic absorption spectrometry with sodium hydroxide as a chemical modifier. Chi-Ren Lan. Ashing temperatures up to 1400°C markedly reduces the background signal caused by high sea-salt contents, while the ashing time is prolonged up to 100 s. The proposed method was used for the direct determination of cadmium in open ocean sea-water. The validity of the procedure was checked with two certified reference sea-waters. A detection limit of 0.015 ng m l - 1 was obtained for 80 gI injections. To reduce interferences from the sea-water matrix during the Cd-determination NaOH was used as chemical modifier to precipitate Mg(OH)2 and coprecipitate Cd, which can be charred consequently at higher temperatures as usual and determined by ET-AAS. Analyst 118, 189 - 192 (1993). Chem. Lab., Power Res. Inst., Taiwan Power Comp., Taipei 23802 (Taiwan) Determination of rhenium and platinum in natural waters and sediments, and iridium in sediments by flow injection isotope dilution inductively coupled plasma mass spectrometry (ID-ICPMS). D.C. Colodner, E.A. Boyle and J.M. Edmond. Re, Ir and Pt can be determined in natural samples as sea water, river water, sediment pore water and sediment by ID-ICPMS. A stable isotope-enriched spike is added to the sample before processing. Sediments are dissolved in all-Teflon digestion vessels using a modified standard kitchen microwave oven. Anion exchange of the chloro complexes of Ir and Pt and of the perrhenate ion ( R e O 4 ) is used to preconcentrate the elements and to separate them from concomitants which produce molecular ions in the argon plasma resulting in isobaric interferences. Samples are then introduced into the ICPMS in a small volume (300-600 gl) using flow injection. Overall recoveries were 90 _+ 10% for all three elements, although the effects of variable recovery efficiency were minimized by the isotope dilution technique. The method has detection limits (S/N = 3) of approximately 5 pg of Re, 6 pg of Ir, and 14 pg of Pt. -- Anal. Chem. 65, 1419-1425 (1993). Dept. Earth, Atmosph. and Planet. Sci., Massachusetts Inst. Techn., Cambridge, M A 02139 (USA) Determination of trace mercury in the environmental water containing iodide by using cold-vapor atomic absorption spectrometry. E. Yamada, T. Yamada and M. Sato. Trace mercury can be determined by cold-vapor atomic absorption analysis after the reduction of mercury with a mixture of sodium tetrahydroborate (NaBH4) and tin(II) chloride in acidic solution. Iodide up to 20 mg/20 ml did not interfere with the mercury determination, and 85% recovery of mercury was attained even in the presence of 100 mg of iodide. The present method was successfully applied to the determination of mercury in wastewater discharged from universities, research institutes and so on. The mechanism of the interference of iodide was investigated. - Anal. Sci. 8, 863--868 (1992). Cent. Environ. Sci., Inst. Technol., Matsugasaki, Kyoto 606 (J) Determination of ammonia as its benzenesulphonyldimethylaminomethylene derivative in environmental water samples by gas chromatography with flame photometric detection. H. Kataoka, S. Ohrui, A. Kanemoto and M. Makita. Ammonia can be analyzed as its benzenesulfonyldimethylaminomethylene derivative by G C / F P D on a DB-I capillary column. The derivative was very stable on standing in ethyl acetate, eluted as a

202 single peak and provided an excellent response in the flame photometric detector. A linear calibration graph was obtained in the range 2 - 4 0 nmol of ammonia. The detection limit of ammonia was about 1.5 pmol injected. Ammonia in environmental water samples could be measured without interference from co-existing substances. The recoveries of ammonia were 95.0-97.5% and the relative standard deviations were 3.3 6.0%. - J. Chromatogr. 633, 311-314 (1993). Fac. Pharm. Sci., Univ., Tsushima, Okayama 700 (J) Segmental flow injection with ion-selective electrodes for the determination of fluoride in water. J.A. Borzitsky, A.V. Dvinin, O.M. Petrukhin and Yu.I. Urusov. A flow analysis system has been developed combining the advantages of the injection technique and air segmentation with improved performance characteristics in comparison to conventional CFA and FIA system. Parameters of the analyser were optimized to ensure the highest rate of analysis allowed by the bubble-through flow cell with fluorideselective electrodes. Fluoride was determined in 0.1 ml water samples with a sampling rate as high as 720 h - ~ and a relative standard deviation better than 1%. -- Anal. Chim. Acta 274, 125-128 (1993). Sillamae Chem.-Metallurg. Enterprise, Sillamae 202010 (Estonia) Ion-exclusion chromatographic determination of hydrogen carbonate in natural waters using unmodified silica gel and conductimetric detection. M. Zenki, T. Nabekura, A. Kobayashi, T. Iwachido and Y. Shimoishi. Unmodified silica gel can be used for the separation of riCO3 - by IEC. By elution with water and monitoring with a conductimetric detector, excellent separation can be achieved. The chromatographic conditions for the separation of hydrogen carbonate, pore and particle sizes of packings and the separation mechanism are discussed. For the determination of hydrogen carbonate, borate buffer solution (pH 7.3) was added. The calibration graph was linear in the range 2 - 2 0 lag ml-1 of hydrogen carbonate. Common anions and cations such as chloride, nitrate, sulfate, sodium and calcium do not interfere. The method has been applied to the determination of hydrogen carbonate in river and lake waters. - Analyst 118, 273-276 (1993). Dept. Chem., Fac. Sci., Univ. Sci., Ridai-cho, Okayama 700 (J) Ion chromatography of nitrite and carbonate in inorganic matrices on an octadecyl-poly(vinyl alcohol) gel column using acidic eluents. S. Rokushika, F.M. Yamamoto and K. Kihara. Low levels of carbonate and nitrite contained in inorganic matrices as brine were determined by ion chromatography on an Asahipak ODP50 poly(vinyl alcohol) gel-based reversed-phase column. With an acidic mobile phase as 1 mM sulphuric acid inorganic matrix anions and cations eluted near the void volume of the column, whereas carbonate and nitrite were retained and separated completely from the matrix ions. After the separation column, the peak response was enhanced using a cation-exchange hollow fibre and 25 mM sodium sulphate or alkaline enhancers. Sea-water samples can be applied directly for the determination of carbonate and added nitrite at ppm levels. The maximum sample volume that can be loaded on the column without peak deformation depended on the pH of the sample solution and the sulphuric acid concentration in the eluent. A 50 lal sea-water sample was applicable with a 2.5 mM acid eluent. - J. Chromatogr. 630, 195-200 (1993). Dept. Chem., Fac. Sci., Univ., Kyoto 606-01 (J) Ion interaction chromatography with nonylamine reagent for the determination of nitrite and nitrate in natural waters. E. Pobozy, B. SwerydaKrawiec and M. Trojanowicz. The ion interaction chromatographic determination of inorganic anions was optimiied using C18 reversed-phase columns modified with nonylamine with special regard to the determination of nitrate and nitrite. The eluent was 2.0 mM nonylammonium phosphate of pH 6.5 and the UV detection wavelength was 205 rim. For a sample volume of 200 gl detection limits of 2.0 and 1.5 lag/1 were obtained for nitrite and nitrate, respectively. The change of the detection wavelength to 190 nm enables also the quantitative detection of chloride. Results obtained for natural waters have been correlated with thosej obtained using standard spectrophotometricprocedures. - J. Chromatogr. 633, 305 - 310 (1993). Dept. Chem., Univ., 02-093 Warsaw (PL)

2 Particular matrices and fields of application Microchemical determination of iodate and iodide in sea waters by flow injection analysis. K. Oguma, K. Kitada and R. Kuroda. An FIA method for iodate and iodide in sea water is described based on the catalytic, fading effect of either iodate or iodide on the indicator reaction with iron(III) thiocyanate and nitrite. With and without an anion-exchange column in the flow conduit, the system allows the determination of iodate and total iodine, respectively; iodide can be found as difference. Both iodate-iodine and total iodine can be determined in the range 0.75 to 150 lag/1 with analysis times of 20 min for iodate-iodine and 9 rain for total iodine. The RSDs are within 1.3% for both iodate and iodide. Results are presented for the determination of iodate and iodide in sea waters and some brines. - Mikrochim. Acta 110, 7 1 - 7 7 (1993). Lab. Anal. Chem., Fac. Engin., Univ. Chiba, Inage-ku, Chiba 263 (J) Experience with the ion chromatographic determination of sulfite. F. Schmitz and M. Kaiser. Sulfite determination in water samples in the low microgram range (working range > 0.1 rag/l) can be carried out using ion chromatography. Good results were obtained with Dionex columns with 0.002 mol/1 Na2CO3 and 0.00075 mol/1 NaHCO3 as eluents. The addition of formaldehyde to the sample guarantees a preservation of sulfite in the samples for 72 h. A careful determination of the influence of the matrix is necessary. Using conductivity and UV-detection simultaneously the sensitivity for real samples can be optimized. - GIT Fachz. Lab. 38, 13 17 (1993). Hess. Landesanst. Umwelt, W-6200 Wiesbaden (D) Experiences with the ion chromatographic determination of sulfite. F. Schmitz and M. Kaiser. Ion chromatography is a usable tool for the determination sulflte in water. By addition of formaldehyde a preservation up to 72 h can be obtained. The chromatography is carried out on a Dionex HPIC AG9 + HPIC AS9 column with carbonate-containing eluents. Cross sensitivities (e.g. interfering ions, special matrix interferences) may occur in environmental samples. The precision in waste water analysis can be increased by the simultaneous use of a conductivity and a UV detector. DIN and ISO working groups worked out proposals for ion chromatographic methods. The working range of ion chromatographic method is in the low microgram range. - GIT Fachz. Lab. 37, 5 - 1 1 (1993). Inst. Anorgan. Chemic, Univ., Hannover (D) A fluorescence quenching method for the determination of chlorine in water with 2,3,7-trihydroxy-9-dibromo-hydroxy-phenylfluorone and cetyltrimethylammoninm bromide. Guoquau Gong, Liufaug Wang, Fengqin Wang and Liqian Li. To determine chlorine in water a highly sensitive and selective fluorescence quenching method at 495/520 nm was developed based on the reaction with 2,3,7-trihydroxy-9-dibromo-hydroxy-phenylfluorone as fluorogenic reagent in the presence of CTMAB. The detection limit is 0.10 lag/25 ml. The linear calibration range is 0.10-3.0 lag/25 ml. Anal. Lett. 26, 147-151 (1993). Dept. Chem., Lanzhou Univ., Gansu 730000 (RC) Low level determination of formaldehyde in water by high-performanc liquid chromatography. E. Cotsaris and B.C. Nicholson. Formaldehyde in water was determined by derivatization with 2,4dinitrophenylhydrazine at an optimized pH (1.5-2.5), solid-phase extraction with C18 adsorption cartridges and analysis by reversed:phase HPLC/UV detection with acetonitrile/water (65: 35). Adsorption of aldehydes on anion-exchange resin (HSO3 -form) resulted in lowering the detection limit to 0.1 lag/1for a 200 ml sample. The use of C1 a adsorption cartridges also minimized background effects. The recovery of C 1 - C 3 aldehydes spiked into purified blank water was 83 - 9 3 % with a relative standard deviation of 1.4-6.4%. - Analyst 118, 265-268 (1993). Austr. Cent. for Water Qual. Res., Priv. Mail Bag, Salisbury, S.A. 5108 (AUS) Determination of nanomolar concentrations of individual dissolved low molecular weight amines and organic acids in seawater. Xiao-Hua Yang, C. Lee and M.I. Scranton. Highly soluble organic compounds can be concentrated from sea water samples by diffusion of these compounds across a hydrophobic

2.3

203

Environmental matrices

membrane. This step separates them from sea salts and most of the other organic compounds dissolved in sea water. Amines or organic acids in the concentrated sample are then quantified by gas chromatography. Concentration factors up to 1000 can be achieved. Concentrations of various amines and organic acids obtained using this method are reported for coastal and estuarine seawater, sediment pore waters, and a freshwater lake. - Anal. Chem. 65, 572-576 (1993). Marine Sci. Res. Center, State Univ. New York, Stony Brook, NY 11794-5000 (USA) Detection of substituted benzenes in water at the pg]ml level using solidphase microextraction (SPME) and gas chromatography[ion trap mass spectrometry. D.W. Potter and J. Pawliszyn. To detect benzene, toluene, ethylbenzene and xylene isomers (BTEX) in environmental waters solid-phase microextraction (SPME) is combined with gas chromatography/ion trap mass spectrometry (GC/ITMS). The combined method SPME/GC/IT-MS, using fibers coated with a 100 ~m polydimethylsiloxane coating, showed a limit of quantitation (LOQ) of 50 pg/ml benzene in water. The limit of detection (LOD) was 15 pg/ml benzene. The detection limits obtained exceed the requirements of both the United States Environmental Protection Agency method 524,2 and the Ontario Municipal/Industrial Strategy for Abatement program, which range from 30 to 80 pg/ml and 500 to 1100 pg/ml, respectively. The linearity of the method extended over five orders of magnitude. Relative standard deviation ranged from 2.7 to 5.2% for 15 ng/ml BTEX in water and from 5.5 to 7.5% for 50 pg/ml BTEX in water. - J. Chromatogr. 625, 247-255 (1992). Waterloo Cent. Groundwater Res., Univ., Waterloo, Ontario N2L 3G1 (CDN) Determination of selected chlorinated benzenes in water by purging directly to a capillary column with whole column cryotrapping and electron-capture detection. S.A. Rounds and J.F. Pankow. The purge with whole column cryotrapping (P/WCC) method for the determination of volatile organic compounds (VOCs) in aqueous samples is adapted for use with an electron-capture detector. In this method, VOCs are stripped from an aqueous sample with an inert purge gas and transferred directly to the head of a capillary column for subsequent GC analysis. A glass-bead water trap (0.32 cm O.D. stainlesssteel tubing filled with 0.5 mm diameter glass beads) is placed in-line between the purge vessel and the gas chromatograph. By maintaining the trap at - 10°C during the purge, most of the water can be removed from the purge gas. Transmission of the analytes to the column is then achieved with a subsequent, short purge of the trap at 25°C. The method was tested with the chlorinated benzenes. This method allows the simplicity and the high reliability of the P/WCC method to be combined with the exceptionally high sensitivity of an electron-capture detector. J. Chromatogr. 629, 321-327 (1993). Dept. Environ. Sci., Engin. Grad. Inst., Beaverton, OR 97006-1999 (USA) Determination of ultra-traces of anthracene in water samples by solidphase spectrofluorometry (SPF). L. Capitan-Vallvey, E.J. Alonso, R. Avidad, M. de10lmo and J.L. Vilchez. Anthracene is fixed on C-18 silica to give fluorescence at )~ex = 357 nm and )~ex = 405 nm wavelengths. An anthracene/silica-gel system packed in a 1 mm quartz cell was measured directly using a solid-surface attachment. The applicable concentration range was 50-1000 ng dm-3 with a relative standard deviation of 0.7% and a detection limit of 21 ng dm 3. The method was applied to the determination of anthracene in natural, tap and seawater samples. The recoveries were 100, 105 and 110%, respectively. The method is very simple and more sensitive than other methods described in the literature. Sigma C-18 silica gel can be used for the rapid determination of anthracene ultratraces in water by SPF in the presence of up to 11 PAHs as well as seven fluorescent and non-fluorescent pesticides. - Anal. Sci. 9, 117-121 (1993). Dept. Anal. Chem., Univ. Granada, E-18071 Granada (E) Determination of fatty and resin acids in waste water after biological treatment using capillary gas chromatography. J. Stufka-Olczyk and B. Pszonka. Fatty and resin acids in waste water from pulp and paper mill after biological treatment were isolated using the ethyl ether extraction or sorption on DIAION HP-2 sorbent and then they were converted into

volatile ester derivatives. The esters were separated on the DB-1 nonpolar capillary chromatographic column. Identification of individual acids was carried out with retention coefficients determined using standards. The quantitative analysis was carried out with the method of internal standard. - Chem. Analit. 37, 307-312 (1992). Pulp, Paper Res. Inst., 90-950 Lode (PL) Determination of trace amounts of morpholine and its thermal degradation products in boiler water by HPLC. M. Joseph, V. Kagdiyal, D.K. Tuli, M.M. Rai, S.K. Jain, S.P. Srivastava and A.K. Bhatnagar. To determine morpholine and its amine-type thermal degradation products in boiler water the substituted amides with N-succinimidyl-pnitrophenyl-acetatewere used for HPLC separation on a Supelcosil-ODS column with 65% water (+ 0.01 M Na-acetate buffer)/35% methanol as isocratic mobile phase and UV detection at 280 nm. Morpholine and its breakdown products were monitored in the range 0.01-10 ~g m1-1 with a relative standard deviation of 0.4-3.0%. - Chromatographia 35, 173-176 (1993). Indian Oil Corp. Ltd., Res. Develop. Centre, Faridabad-121007 (IND) Determination of non-ionic surfactants in waste water by direct extraction with Fourier transform infrared spectroscopic detection. B.E. Andrew. Non-ionic surfactants in waste water can be extracted and concentrated in dichloromethane using a simple salting-out procedure. The characteristic C-O-C stretch vibration of the ethoxylate compounds at 1110 cm- 1 is then utilized to measure surfactant concentration at levels ranging from 0.1 to 50 mg 1-1. Relative standard deviations vary from 15% at the 10 mg 1-1 level for a single-step extraction, to 5% at the 1 mg 1-1 level for multiple extraction followed by evaporation and reconstitution. Soaps interfere. A comparison with the known cobaltothiocyanate method has been carried out, extraction with FT-IR is more accurate concerning recovery. -- Analyst 118, 153--155 (1993). BHP Sheet & Coil Prod. Div., Hastings 3915 (AUS) A simple spectrophotometrie determination of endosulfan in river water and soil. J. Raju and V.K. Gupta. A simple spectrophotometric determination of endosulfan (Thiodan), a sulphur containing pesticide is desribed. The method is based on the liberation of sulphur dioxide from endosulfan which is subsequently absorbed into an absorbing reagent, malonyldihydrazide and estimated by using p-aminoazobenzene and formaldehyde to give a pink coloured dye which has an absorbance maximum at 505 nm. The Beer's law is obeyed in the range of 1 - 6 ppm for a standard solution of endosulfan. The method can be easily applied in river water and soil samples to determine endosulfan level as low as 0.05 ppm and 0.25 ppm in river water and soil, respectively. The method is free from the interference of most of the commonly used pesticides and other common ions. - Chem. Analit. 37, 245-248 (1992). Dept. Chem., Ravishankar Univ., Raipur M.P. 492010 (IND) Analysis of pesticides in ground and drinking water. M. Wotschokowsky. 19 groups of pesticides can be enriched on 1 g LiCrolut RP-18 extraction cartridges from 1 1 water samples with sufficient recoveries. The elution is carried out with methanol/acetonitrile (1:1) and the HPLC analysis on a LiChrospher RP-select column with a gradient between 0.5 mM sodium acetate and acetonitrile and UV detection at 215 nm. GIT Fachz. Lab. 37, 404-408 (1993). E. Merck, W-6100 Darmstadt

(D) Gas chromatography for determination of pesticides in aquatic systems Experience from a governmental laboratory. W. Gilsbach. The applicability of gas chromatography for the determination of pesticides in aquatic systems is reviewed especially from the view of an official laboratory. Potential and limitations of different methods for derivatization, chromatographic separation and detection are discussed. The analytical strategies for determination of pesticides with different chemical properties are given presenting examples from governmental laboratory analytical experience. [21 References] - Acta hydrochim. hydrobiol. 21, 89-102 (1993). Landesunters.amt Gesundheitswesen Nordbayern, W-8520 Erlangen (D)

204 Gas chromatography for determination of pesticides in aquatic systems Analytical basis. H.-J. Brauch. An overview is given over the possibilities of utilization of high resolution gas chromatography (HRGC) with ECD, NFID and MSD as a very efficient determination method for pesticides in water. Because of their relatively low concentrations in aquatic systems enrichment and preconcentration procedures are essential. Some examples for pesticide determination of GC methods are given. Potentials and limitations of HRGC for pesticide analysis are also discussed. An extensive pesticide analysis in water has to include different methods like HRGC, HPLC and GC/MS. [15 References] - Acta hydrochim, hydrobiol. 21, 8 4 - 8 8 (1993). DVGW-Forsch., Univ. Karlsruhe (TH), W-7500 Karlsruhe 1 (D) Determination of organophosphorus and organouitrogen pesticides in water and sediments by GC-NPD and GC-MS. S. Lartiges and P. Garrigues. An analytical procedure has been developed for the determination of 30 organophosphorus (OP) and 8 organonitrogen (ON) compounds in the aquatic environment (water, sediments). OP and ON were analyzed by GC equipped with cool on-column injectors and coupled either with a nitrogen-phosphorus detector (NPD) or with a mass selective detector (MSD) in electron impact (EI) and positive chemical ionisation (PCI) modes. Chromatographic retention indexes based on a series of organonitrogen internal standards were defined for GC-NPD in order to confirm analytes in environmental samples. The retention indices obtained on CPSIL-8-CB columns are tabulated. Detection limits of about 200 pg can be achieved. - Analusis 21, 157 165 (1993). URA 348 CNRS, Univ. Bordeaux I, 33405 Talence Cedex (F) Determination of eight organochlorine pesticides at low nanogram[liter concentrations in groundwater using filter disk extraction and gas chromatography. B.A. Tomkins, R. Merriweather, R.A. Jenkins and C.K. Bayne. A rapid, quantitative and convenient procedure to determine 8 organochlorine pesticides routinely at levels below I 0 parts per trillion (ng/ l) in natural groundwaters is described. Analytes are extracted rapidly from 1 1 groundwater samples by using conditioned Teflon filter disks impregnated with silica containing bonded octadecyl phase. Filter is dried briefly under vacuum, and pesticides are eluted with 10 ml ethyl acetate. The extract is dried with about 1 g anhydrous sodium sulfate and then concentrated to exactly I ml. Pesticides are separated in a gas chromatograph equipped with a capillary column, detected by a highsensitivity electron capture detector, and quantitated by the method of external standards. Certified reporting limit (CRL) values for the 8 pesticides ranged between 2 and 7 ng/1. - J. AOAC Intern. 75, 1091 1099 (1992). Nat. Lab., Org. Chem. Sect., Anal. Chem. Div., Oak Ridge, TN 37831-6120 (USA) Rapid determination of chlorinated pesticides using CN-bonded cartridges followed by GC-ECD. M.V. Russo, G. Goretti and A. Liberti. Gas chromatography of chlorinated pesticides in water is carried out after adsorption of a 50 ml sample using a cartridge containing 100 mg CN-bonded porous silica and extraction with 500 ~tl pentane on a SE54 glass capillary column with 63Ni-ECD. The average recovery for eight organochloride pesticides at 1 ppb was >95%. The procedure described is simple, selective and reproducible. The smallest detectable concentrations are 0.3 gg/1 for 2.4:DDT and 0.1 ~tg/1 for other chlorinated pesticides. -- Chromatographia 35, 290 - 294 (•993). Dipt. Chim., Univ. "La Sapienza", 1-00185 Rome Micellar enhanced spectrofluorometric determination of chlorophyll a and chlorophyll b in fresh waters. J.J. Santana, M.A. Gunshefski and J.D. Winefordner. A new, very sensitive and selective method for the determination of chlorophyll a and b in environmental samples with Triton X-100 as fluorescence enhancer is developed. After optimization of the variables high recovery percentages are found when the method is applied to the simultaneous determination of chlorophyll a and b in synthetic mixtures. The method is used for the determination of both chlorophylls in local fresh waters, finding excellent agreement with the results obtained by

2

Particular matrices and fields of application

an HPLC/fluorescence method. - Talanta 39, 195-200 (1992). Dept. Chem., Univ., Gainesville, FL 32611 (USA)

Determination of thallium in soils by flow-injection/differential pulse anodic stripping voltammetry. Z. Lukaszewski and W. Zembrzuski. A relatively simple and quick method for the determination of thallium in soils and geological samples is described. The method does not require any separation prior to determination. Total decomposition of the sample was performed in a teflon bomb. The interferences of iron, aluminum and manganese were removed by media exchange performed in a flow-injection measuring system, and the other interferences were removed by the use of the base electrolyte consisting of 0.15 M EDTA and 0.1 M ascorbic acid. A detection limit of 10 ppb (with 0.5 g soil) an be achieved after 10-15 rain preconcentration. - Talanta 39, 221 --227 (1992). Inst. Chem., Techn. Univ., PL-60-965 Poznan Metal speciation studies on sewage sludges of urban origin using sulphurous acid solution spiked with 3ss. L. Campanella, B.M. Petronio, M. Soldani, M. Alessio, L. Allegri and S. Improta. Metal speciation in sewage sludge can be carried out using a sulphurous acid solution (pH 1.5) and sequential extractions with organic solvents. The acid can react with the organic matter as well. The addition of - S O 3 H groups to the double bond which results in an increase in solubility and the breaking action on high molecular mass compounds provides informations about the matrix and on the speciation of metals. - Analusis 21, 167-172 (1993). Dept. Chem., Univ., 00185 Rome (I) Extraction and analysis of diesel fuel by supercritical fluid extraction and microbore supercritical fluid chromatography. M.W. Brooks and P.C. Uden. Soil contaminated by Diesel spills can be extracted with snpercritical CO2. Extraction efficiency was greater than 90% regardless of the organic content of the soil and even after the soil had been aged for five days before analysis. Analysis of extracts by microbore supercritical fluid chromatography provided rapid characterization while GC-MS was used for analysis of residue levels. - J. Chromatogr. 637, 175-179 (1993). Dept. Chem., Univ., Amherst, MA 01003 (USA) Determination of butyltin compounds in river sediment samples by gas chromatography/atomic absorption spectrometry following in situ derivatization with sodium tetraethylborate. Yong Cai, S. Rapsomanikis and M.O. Andreae. The application of the ethylation technique for the determination of butyltin compounds in environmental samples is described based on the in situ ethylation of organotins by sodium tetraethylborate in acqueous buffered solution, simultaneous purging and trapping of ethylation derivatives and detection by AAS. The absolute detection limits (3~ of baseline noise) for mono-, di- and tributyltin are 0.08, 0.34 and 0.11 ng of tin, respectively. The concentration detection limits achieved are 9, 38 and 12 ng of tin per gram of sediment (dry mass), respectively. J. Anal. At. Spectrom. 8, 119 - 125 (1993). Biogeochem. Dept., Max Planck Inst. Chem., W-6500 Mainz (D) Extraction of organophosphorus pesticides from soil by off-fine supercritical fluid extraction. K. Wuchner, R.T. Ghijsen, U.A.Th. Brinkman, R. Grob and J. Mathieu. SFE with the use ofpre-mixed methanol-modified CO2 or the addition of methanol to the soil samples yields in almost quantitative (~>90%) recoveries of most organophosphorus pesticides (OPPs) from soil in less than 15 min. All OPPs except dimethoate can be quantitatively recovered from inert matrices such as glass-wool and sand, and from spot-spiked soil samples using pure CO2 at 50°C and 250 bar. -- Analyst 118, 11 16 (1993). Dept. Anal. Chem., Free Univ., 1081 HV Amsterdam (NL) Determination of chlorophenols and chlorobenzenes in leachate by headspace analysis. C. F6rst, H. Simon and L. Stieglitz. Chlorophenols, chlorobenzenes and hexachlorocyclohexanes in water and leachate samples can be determined using headspace analysis. Detailed calibration tests were performed with one isomer of each chlorination degree in aqueous reference samples. Linearity was observed for

2.4

Foods

all of the components investigated with the corresponding correlation coefficients > 0,995. - Chemosphere 26, 1355-1365 (1993). Kernforschungszentrum Karlsruhe, Postf. 3640, W-7500 Karlsruhe 1 (D) Determination of pesticides in soil samples by solid phase extraction disks. M.J. Redondo, M.J. Ruiz, R. Boluda and G. Font. The use of SPE C8 disks provides a simple, rapid, accurate, reproducible and economical technique for the extraction of the pesticides Molinate, Atrazine, Carbofuran, Pirimicarb, Promethryn, Malathion and Tetrachlorvinphos from soil. The analyses were carried out by capillary gas chromatography with nitrogen and phosphorus detection. Recovery experiments were performed at ppb levels in spiked soil samples. The average recoveries of the compounds were 5 3 - 7 7 % . Detection limits are between 5 and 30 ng g - 1 based on 5 g moist soil sample. The method was validated by comparing it with conventional liquid-liquid extraction. - Chromatographia 36, i 8 6 - 1 9 0 (1993). Lab. Toxicol., Fac. Farm., Univ. Valencia, 46100 Burjassot, 46010 Valencia (E) Individual determination of ortho and non-ortho substituted polychlorobiphenyls (PCBs) in sediments by high-performance liquid chromatographic pre-separation and gas chromatography/ECD detection. R. Fuoco, M.P. Colombini and E. Samcova. An analytical scheme for the analysis of sediment samples is proposed in which ortho and non-ortho PCBs can be separated and determined. The n-hexane/acetone (1 : l) extracts are treated with Cu and Hg, cleaned on a Florisil column, preseparated by HPLC on a graphite column and analyzed by GC/FTIR and GC/MS. Recovery and precision were typically 83% and 16% respectively at 2 ng/g of total PCB content. The proposed procedure, tested by analyzing real sediment samples, showed a reproducibility better than 20% at ] 3 ng/g PCB level. Chromatographia 36, 6 5 - 7 0 (1993). Ist. Chim. Anal. Strument., CNRA, Pisa (I) Gas chromatographic method for the determination of anilophos in soil. S.B. Singh and G. Kulshrestha. For the GC determination of anilophos flame photometric and nitrogen-phosphorus detection (NPD) were more sensitive than flame ionization and electron-capture detection. The method was extended to the determination of anilophos residues in soil using NPD. The recoveries of anilophos from soil with ethyl acetate (95--102%) were significantly higher than those with dichloromethane (80 88%) and methanol ( 4 4 49%). J. Chromatogr. 637, 109-112 (1993). Div. Agricult. Chem., IARI, New Delhi 110012 (IND) Residues of herbicides in soils. K. Michels. Several analytical methods for the determination of herbicide residues in soils are described using HPLC with different column- and gradient elution systems and UV- and diode-array detection. The determination limit of some herbicides lie in the range of 0.01 mg/kg soil. The herbicides firstly are analysed with reversed-phases and acetonitrile-water gradient systems. To evaluate this method phases with similar polarity like normal phases can be used in connection with hexane-isopropanoI gradient systems. In most cases expensive clean-up steps are avoidable. Commercial solid phase extraction cartridges are sufficient to get clean extracts. GIT Fachz. Lab. 38, 28--33 (1993). LUFA Augustenberg, W7500 Karlsruhe (D)

2.4

Foods

Extraction and separation of potential migrants from food contact materials and articles using supercritical carbon dioxide. T. Bficherl, A.L. Baner and O.-G. Piringer. A simple and quick SFE/SFC method has been developed for the determination of potential migrants. Different additives can be deter-

205 mined using supercritical CO2 as extraction phase. The method can be used as screening test for food contact materials. - Dtsch. Lebensm. Rdsch. 89, 69-71 (1993). Fraunhofer Inst. Lebensm. Technol., W-8000 Mtinchen 50 (D) A rapid HPIC method for the quantitative determination of tetranlethylammonium chloride in some aqueous solutions used as food simulants. M. Boccacci Mariani, M.R. Milana, S. Giamberardini and S. Cavalli. Tetramethylammonium chloride, used in the production of epoxycoated tin plate cans, can be determined in aqueous food simulants (water, 3% acetic acid, 15% ethanol, mixture 3% acetic acid/15% ethanol) by HPLC on a polystyrene/divinylbenzene column with 0.06 M HC1/0.006 M 2,3-aminopropionic acid as mobile phase. The method has been applied to the determination of unreacted tetramethylammonium chloride residues which are able to migrate from finished epoxy resins which are used as food packaging materials. - Chromatographia 36, 362-364 (1993). Ist. Merceol., Univ. "La Sapienza', 1-00161 Rome (I) Determination of pyromellitic acid in aqueous matrices by HPLC. M. Boccaci Mariani, N. Fagnano, M.R. Milana and A. Pinto. A rapid method for the HPLC determination of pyromellitic acid in aqueous media used as "food simulants" has been developed. An Omnipak PAX 100 seperator column and a mobile phase composed of 0.002 M NaOH/0.3 M NaCl-acetonitrile (75:25) was used. A detection limit of 20 gg/1 was computed (S/N=5). The proposed method can determine pyromellitic acid at ppb trace levels and is based on an ion exchange separation mechanism. The method has been applied to the determination of pyromellitic acid residues leached from plastic bottles. - Chromatographia 36, 3 6 5 - 367 (1993). Ist. Merc. Univ. "La Sapienza", 1-00161 Rome (I) High performance ion chromatography determination of nitrite and nitrate in foodstuffs. M.I. Santillana, E. Ruiz, M.T. Nieto and M. de Alba. To detect nitrite and nitrate simultaneously even in the presence of chloride a HPLC method using an anion-exchange polymethacrylate column and 5 mM phosphate buffer (pH 6.5) and UV absorbance at 214 nm is developed. The detection limit was 0.5 I~Lg/mlfor both anions. This method was shown to be applicable to the analysis of several foodstuffs. - J. Liquid Chromatogr. 16, 1561-1571 (1993). Serv. Bromat., Centr. Nac. Alim., C. Majadahonda-Pozuelo, Km. 2,2, E28220 Madrid (E) HPLC using diol-bonded silica, an alternative to silical gel in the prefractionation of aroma extracts. D. Barron. A strawberry jam dichloromethane aroma extract was pre-fractionated by normal phase HPLC on diol. This was preceded by neutralization with aqueous sodium bicarbonate, and removal of fatty acids by gel filtration on Sephadex LH-20. Elution of the diol column with a gradient of diethyl ether in pentane resulted in the separation of two main fractions. One contained hydrocarbons and carbonyl compounds, whereas lactones and polar compounds such as hydroxylated carbonyl compounds or alcohols were present in the second fraction. - Z. Lebensm. Unters. Forsch. 193, 454-459 (1991). Lab. Rech. Ardmes, INRA, BP 1540, F-21034 Dijon Cedex (F) Chirospecific analysis in essential oil, fragrance and flavor research. P. Werkhoff, S. Brennecke, W. Bretschneider, M. Giintert, R. Hopp and H. Surburg. Knowledge of the difference in character and intensity of organoleptically important enantiomeric flavor and fragrance components has initiated the development of new analytical and preparative methods for the separation of optical isomers. In recent years, progress in the area ofchirospecific analysis has been especially achieved by the development of modified cyclodextrins as a new type of chiral stationary phase. The state of the art in research on inclusion gas chromatography for separating flavor and fragrance substances is presented. Furthermore this review reports on new results and recent research developments in enantioselective GC analysis. 16i References. - Z. Lebensm. Unters. Forsch. 196, 307 328 (1993). Haarmann & Reimer GmbH, Corp. Res., W-3450 Holzminden (D)

206 An improved HPLC system for the analysis of photosynthetic pigments. G.W. Francis, B. Huseby and O.M. Andersen. A HPLC system for the analysis of photosynthetic pigments with an octadecylsilica stationary phase, a programmed quaternary mobile phase consisting of mixtures of methanol, acetonitrile, water and hexane, and a photodiode array detector is presented. Carotenoids and chlorophylls are rapidly analysed in a single chromatographic run. The cis-trans isomers of most carotenoids are separated by this method. Chromatographia 35, 189-192 (1993). Dept. Chem., Univ. Bergen, N5007 Bergen Synergistic extraction-atomic spectrophotometric determination of vanadium in foods and petroleum crudes with 5,5'-methylenedisaficylohydroxamic acid (MEDSHA). G. Bagur, D. Gasquez, M. Sfinchez and A. Martin. A flame AAS method is developed for the determination of vanadium, down to microgram level, in food samples and petroleum crudes. The procedure is based on the synergistic extraction of the V(V)-MEDSHAcomplex with a 0.5 M tributyl phosphate solution in isobutyl methyl ketone at pH 1.0-1.5. The method is highly selective and has a detection limit of 0.019 txg ml-1 (Vorg./Vaq. = 0.2) and of 0.006 gg mI-1 (Vorg./ Vaq. = 0.05), with a relative standard deviation not exceeding 1.5% at a level of 2 gg ml- 1 and 3% at a level of 0.4 gg mi- 1. Interferences from other ions can be minimized with the exception of those from Mo(VI). Anal. Lett. 26, 125-140 (1993). Dept. Anal. Chem., Fac. Sci., Univ., 18071 Granada (E) Rapid quantitative determination of free fatty acids in fats and oils by Fourier transform infrared spectroscopy. A.A. Ismail, F.R. van de Voort, G. Emo and J. Sedman. Simple, rapid direct and indirect Fourier transform infrared (FTIR) spectroscopic methods were developed for the determination of free fatty acids (FFA) in fats and oils based on both transmission and attenuated total reflectance approaches ( 0 . 2 - 8 % FFA). Calibrations curves were prepared by adding oleic acid to the oil chosen for analysis and measuring the C = O band at 1711 cm-1 after ratioing the sample spectrum against that of the same oil free of fatty acids. For fats and oils oxidized or thermally stressed an indirect method was developed in which 1% KOH/ methanol is used to extract the FFAs and convert them to their potassium salts. The carboxylate anion absorbs at 1570 cm -1. Both approaches gave results comparable in precision and accuracy to that of the American Oil Chemists' Society reference titration method. The FFA analysis procedure was completely automated, making it suitable for routine quality control applications. An analysis takes less than 2 rain. JAOCS 70, 335-341 (1993). Dept. Food Sci., Agricult. Chem., McGill Univ., Ste. Anne de Bellevue, Quebec H9X 1C0 (CDN) Analysis of tocopherols by capillary supercritical fluid chromatography and mass spectrometry. J.M. Snyder, S.L. Taylor and J.W. King. Tocopherol-containing mixtures were analyzed by GC and SFC. GC analysis of tocopherols required the formation of the silyl derivatives, while SFC analysis of the tocopherol-containing mixtures was accomplished on neat samples. SFC analysis conditions were optimized. Enhanced resolution of many components were achieved by using inverse temperature programming during the SFC analyses. Both SFC and GC analyses permitted the separation and quantitation of alpha-, beta-, gamma- and delta-tocopherols. SFC proved particularly applicable for characterizing the composition of a deodorizer distillate and commercial antioxidant formulation. Coupling of a quadrapole mass spectrometer with a supercritical fluid chromatograph was also achieved; the mass spectrometer provided electron impact mass spectra on the underivatized tocopherol and sterol moieties. Both SFC and SFC/MS proved effective for the analysis of complex lipid-containing mixtures, requiring minimal sample preparation prior to analysis. - JAOCS 70, 349--354 (1993). Dept. Agricult., Peoria, IL 61604 (USA) Separation of instrumental and chemical errors in the analysis of oils by gas chromatography - a collaborative evaluation. J. D. Craske. 35 laboratories participated in a collaborative trial to investigate possible errors arising in the GC analysis of the fatty acid composition of

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Particular matrices and fields of application

oils. Errors can be separated into those caused by poor chromatograph optimization and those related to inefficient conversion of triacylglycerols (TAG) to fatty acid methyl esters (FAME). A primary standard mixture of FAME was used to determine how well the participants had optimized their chromatographs. A primary standard of the equivalent TAG was used to determine total error of analysis. "Chemistry error" was calculated as the difference between the absolute errors found for the FAME and the TAG standards. Grades of analysis were computed for the FAME and TAG results and for the chemistry errors calculated from these analyses. - JAOCS 70, 325-334 (1993). Lipid Res. Group, Dept. Food Sci., Univ., Kensington, NSW 2033 (AUS) Gradient elution HPLC of fats and oils with laser fight scattering. K. Aizetmiiller and M. Gr6nheim. Gradient HPLC of oils and fats using reversed-phase HPLC of RP18 columns with laser light scattering detection are described. Potential advantages and shortcomings are discussed. Flexible solvent gradient programming permits an adaption of the system to several kinds of application. Gradients mixed from acetonitrile/2-propanol/hexane or acetonitrile/ethanol/hexane were used. Using systems of this type the usual solubility problem encountered with long-chain triglycides can be easily overcome. A useful test-mixture consisting of a series of saturated triglycerides with two carbon numbers apart can be obtained by interesterfication of hydrogenated palm kernel oil and hydrogenated palm oil. With such HPLC systems the simultaneous investigation of diglycerides and triglycerides in oils is also possible. - Fat Sci. Technol. 95, 164-168 (1993). Inst. Chem. Phys. Lipid, Fed. Centre for Cereals, W-4400 Miinster (D) Determination of vitamin D in margarine. E. Homberg. The only small amounts of vitamin D in margarine can be determined only after an extended purification step which includes cold saponification and extraction of the unsaponifiable on an alumina-digitonin/ celite column. Other impurities are eliminated by HPLC on an adsorption column and elution of the vitamin D-fraction with hexane/2-propanol (99.5:0.5). The final HPLC is carried out on a reversed phase column (Spherisorb ODS2) with acetonitrile/methanol/chloroform (91 : 3:6) as mobile phase, which results in the separation of vitamin D2 and D3. Each of the vitamins can be used as internal standard for the other. At least 10 g of the sample has to be used for the purification steps. In comparison to biological methods this relatively simple HPLC method is of great advantage. - Fat. Sci. Technol. 95, 181-185 (1993). Inst. Chem. Phys. Fette, BA Getreide-, Kartoffel- Fettforsch., W-4400 Miinster (D) Trace enrichment and HPLC analysis of PAHs in edible oils and fat products using liquid chromatography on electron aceeptor stationary phases in connection with reverse phase and fluorescence detection. J.L. Perrin, N. Poirot, P. Liska, A. Thienpont and G. Felix. A new method for multi-PAH determination in lipid matrices is described. The clean-up step is carried out using donor-acceptor complex chromatography with a tetrachlorophthalimidopropyl modified silica. Neutral lipids and other minor components especially tocopherol, which can interfere with the PAH, are eluted with a mixture of hexane/methyltert.-butyl ether. The PAHs are eluted with methylene chloride and analyzed by gradient reversed-phase HPLC on an octadecyl silica column with a gradient elution program from acetonitrile/water (55:45) to 100% acetonitrile. The fluorescent detection is programmed according to the optimal wavelengths for the PAHs. Aromatic compounds are recovered quantitatively. The entire procedure takes 2 h and is therefore faster than those with liquid-liquid extraction steps. - Fat Sci. Technol. 95, 4 6 - 5 1 (1993). Astra Celve, F-926000 Asnieres On-fine LC-GC for the analysis of the minor components in edible oils and fats - The direct method involving silylation. A. Artho, K. Grob and C. Mariani. The direct on-line method for the direct analysis of minor components in oils and fats described by K. Grob, M. Lanfranchi and C. Mariani [J. Chromatogr. 471, 397 (1989)] which was based on the analysis without cleavage of esters was modified. Here the free alcohol/sterols were silylated instead of acylated and the LC fraction transfered to GC is

2.4

Foods

widened to range from the beginning of the LC chromatograms up to the sterol esters• Silylation eliminates some problems, which are observed with the former method i.e. the esterification of free alcohols by free fatty acids in oils and fats of high acidity, and adds information. The wider range of the LC fraction includes squalene and the tocopherols. No data are provided about the precision and accuracy of the data obtained by this method, but they are assumed to be comparable to the former method. - Fat. Sci. Technol. 95, 176-180 (1993). Kantonales Lab. Ziirich, POB, CH-8030 Ziirich HPLC determination of antioxidant synergists and ascorbic acid in some fatty pharmaceuticals, cosmetics and food. J.M. Irache, I. Ezpeleta and F.A. Vega. An isocratic, specific and sensitive reverse-phase HPLC method for the quantitative determination of ascorbic acid and antioxidant synergists (1-tartaric acid, citric acid, lactic acid as lithium lactate and EDTA) in fatty pharmaceuticals, cosmetics and food has been proposed. Two extraction procedures were used; treatment with hot water, and extraction with water from a hexane dilution of the product. Quantitative determinations were performed using a C-18 column and sulfuric acid (pH 1.95) mobile phase. With detection, at 210 nm, lactic acid overlapped with ascorbic acid, but the former could be readily identified by TLC. Ascorbic acid was detected at 254 nm, when lactic acid (as lithium lactate) did not interfere in the analysis. Mean recoveries for tartaric, citric and lactic acids were in the range 96 - 101%. - Chromatographia 35, 232-236 (1993). Dept. Farm., Tecn. Farm., Univ. de Navarra, E31080 Pamplona Development of a new SFE method for rapid determination of total fat content of food. P. Lembke and H. Engelhardt. An SFE method as an alternative to the official solvent extraction is described for the rapid determination of the total fat content in meat. Under optimised conditions (40°C, 410 bar, 750 ml min- 1), quantitative lipid extraction could be performed in only 35 min (compared to 5 - 6 h by the classical method) with an average recovery better than 95%. Food samples must be acid-treated before extraction, otherwise the "free accessible fat" content is determined and not the "total fat" content. By the acid treatment the lipids are separated from the particular sample matrix, prior to extraction, and fixed onto a filter. Extraction is independent of the sample matrix• - Chromatographia 35, 509-516 (1993). Inst. Angew. Phys. Chem., Univ., W-6600 Saarbriicken (D) Quantitative determination of monoglycerides and diglycerides by highperformance liquid chromatography and evaporative light-scattering detection. J. Liu, T. Lee, E. Bobik, Jr., M. Guzman-Harty and C. Hastilow. Neutral lipid classes were separated with normal-phase HPLC on a gChromagasphere SI-60 column at 40°C with a gradient between hexane and hexane/2-propanol/ethyi acetate/10% formic acid (80:10::[0:1). Mono- and diglycerides were determined with an ELSD. The 1,3diacylglycerols were resolved from the 1,2-diacylglycerol positional isomers, although some 1,3-diacylglycerols of low molecular weight interfered with the 1,2-diacylglycerols of high molecular weight. For monoglycerides, the separations between 1-(and 3-)acyl and 2-acylglycerols were optimized only between those pairs with identical fatty acyI groups. Samples were dissolved in a solvent mixture and analyzed without derivatization. The results (monoglyceride) obtained from this method agreed well with those derived from gas chromatographic and supercritical fluid chromatographic methods. - JAOCS 70, 3 4 3 - 347 (1993). Ross Lab., Anal. Res., Serv., Columbus, OH 43216 (USA) Supercritical fluid chromatographic analysis of the propoxylated glycerol esters of oleic acid. X.J. Lu, M.R. Myers and W.E. Artz. Capillary SFC methods were developed for the separation and quantitation of oligomers of propoxylated glycerols and fatty acid-esterified propoxylated glycerols. SFC was carried out on a SB-methyl100 capillary with 100% bonded polysiloxane as stationary phase with CO2 with density programming as mobile phase. The detection was carried out at 325 -400°C using an FID. Samples containing mole ratios (propylene oxide to glycerol) of 5, 8 and 14 were chromatographed. Separation depended primarily upon th e molecular weight or the number

207 of the propylene oxide units. - JAOCS 70, 355-360 (1993). Univ., Urbana, IL 61801 (USA) High-resolution gas chromatographic determination of diacylglycerols in common vegetable oils. N. Frega, F. Bocci and G. Lercker. The gas chromatographic determination of partial glycerides of sunflower (both high- and low-oleic acid varieties), peanut and extra virgin olive oil was studied. Oil samples are treated with squalane as internal standard in benzene and diazomethane in ethylether to esterify free acids to methyl esters and then with trimethyl chlorosilane to convert alcohol groups to TMS derivatives. These derivatives are separated by GC on a polar capillary column like SE52 with a temperature programme from 180 to 350°C. This column allows for the determination of single diacylglycerols separated as a function of the position occupied by the individual fatty acids on the glycerin backbone as well as by the degree of unsaturation of the fatty acids. - JAOCS 70, 175-177 (1993). Dipt. Sci. Tecnol. Alimen. Microbiol., Sez. Ind. Tecnol. Aliment., 1-50144 Firenze Quantitation of potent odorants of virgin olive oil by stable-isotope dilution assays. H. Guth and W. Grosch. The potent odorants of four olive oil samples differing in flavor were quantitated by HRGC and HRGC/MS, and their odor activity values (OAVs) were calculated by dividing the concentrations of the odorants in the oil samples by the flavor threshold values in the oil. The odorants with higher OAVs were contrasted with the different notes of the flavor profiles of the olive oils. It was concluded that the following compounds contributed mainly to the flavor notes given in parentheses: (Z)-3hexenal (green), ethyl 2-methylbutyrate, ethyl isobutyrate, ethyl cyclohexanoate (fruity), (Z)-2-nonenal (fatty) and 4-methoxy-2-methyl2-butanethiol (black-currant-like). The results showed that the calculation of OAVs is an approach to objectify the flavor differences of olive oil samples. - JAOCS 70, 513-518 (1993). Deutsche Forsch. Anst. Lebensmittelchem., W-8046 Garching (D) High-performance liquid chromatography of selected phenolic compounds in olive oils. M. Akasbi, D.W. Shoeman and A. Saari Csallany. To separate and quantitate the major phenolic compounds of the hydroalcoholic extracts of olive oils, hydroxytyrosol, tyrosol, caffeic acid, p-hydroxyphenylacetic acid and homovanillic acid, a gBondapak C18 column with an acetonitrile/water/acetic acid (20 : 90: 0.18, v/v) mixture as a mobile phase was used. Electrochemical detection provided selectivity as well as sensitivity. Using the simple extraction with methanol/water (60:40) in less than 20 min, the procedure can be extended to other oils and other phenolic compounds. - JAOCS 70, 367-370 (1993). Dept. Food Sci., Nutrit., Univ., St. Paul, MN 55108 (USA) Use of tetrabutylalnmouium tribromide for voltametric titration of unsaturation in vegetable oils and fatty acids. J. Berthelot, P.-L. Desb~ne and A. Desb6ne-Monvernay. A near-quantitative bromination of carbon-carbon double bonds of fatty acids and vegetable oil is obtained easily at room temperature in dry chloroform using tetrabutylammonium tribromide as bromination reagent. This reaction followed by a fast voltametric titration is easy and fast, and results show good accuracy and high sensitivity. - JAOCS 70, 277-279(1993). Lab. Chim. Organ. Struct., Univ. P. et M. Curie, 75230 Paris Cedex 05 (F) Identification and quantitation of ~-oryzanol components and simultaneous assessment of tocols in rice bran oil. E.J. Rogers, S.M. Rice, R.J. Nicolosi, D.R. Carpenter, C.A. McClelland and L.J. Romanczyk, Jr. An RP-HPLC method was developed for the simultaneous separation and quantitation of tocopherols, tocotrienols and oryzanols present in rice bran oil. The HPLC separation was carried out on 5 pm ODS-Ca8 colmnn with acetonitrile/methanol/isopropanol (45: 45 : 5) with a water gradient from 5 to 0%. Tocopherols and tocotrienols were quantitated by fluorescence detection and oryzanols (ferulic acid esters of sterois and triterpene alcohols) by photodiode array detection. Chemical ionization mass spectrometry was used to identify cycloartenyl ferulate, 24-methylene cycloartanyl ferulate, campesteryl ferulate, [3-sitosteryI ferulate and cycloartanyl ferulate as the major oryzanols separated by this procedure.

208 The levels of these nutritionally significant components were found to vary in fully processed, edible rice bran oils from different manufacturers. - JAOCS 70, 301 - 3 0 7 (1993). Dept. Clin. Sci., Card.vasc. Res. Lab., Univ. Mass. Lowell, Lowell, MA 01854 (USA) GC-MS characterization and quantification of sterols and cholesterol oxidation products. L. Pizzoferrato, S. Nieoli and C. Lintas. A GC-MS method has been studied for characterization and quantification of the food compounds phytosterols, chlolesterol and cholesterol oxidation products. Separations were carried out on HP-I columns with a temperature program from 70 to 280°C, the MS was performed at 70 eV. The sterols were investigated as their TMS-ether derivatives. Excellent linearity of response has been obtained permitting reliable quantification. - Chromatographia 35, 269 274 (1993). Ist. Naz. Nutr., Food Chem. Unit, 1-00178 Roma

The determination of monoglycerides, diglycerides and triglycerides by HPLC. V. Filip and M. Kleinovfi. The determination of monoglycerides, diglycerides and triglycerides in the normal phase system: Separon SGX-CN (silica gel with phasebonded cyanoethyl) and mobile phase hexane-isopropanol-formic acid (97:3:0.5) by HPLC with refractometric detection, is described. The separation was according to the molecular mass of glycerides, i.e. in groups. This was demonstrated with palmitic, oleic and linoleic acids. The diglycerides and especially monoglycerides of olive and sunflower oils were partly separated according to the equivalent carbon number values of the glycerides. The response factors related to triglycerides were estimated for the glycerides of the fatty acids and oils mentioned above. The value of response factors depends on the number of double bonds of the fatty acids. - Z. Lebensm. Unters. Forsch. 196, 532-535 (1993). Chem.-technol. Hochsch., Inst. Milch-, Fettechnol., Technickfi, CS-16628 Praha 6 Determination of indolic compounds in pig back fat by solid-phase extraction and gradient high-performance liquid chromatography with special emphasis on the boar taint compound skatole. J. Hansen-Moller. 13 indolic compounds including indole and skatoie (both of which are involved in the boar taint) can be determined by HPLC/fluorimetry. A solid-phase extraction method for sample preparation for the determination of the indolic compounds in pig back fat is described. The indolic compounds are extracted with acetone-Tris buffer, and lipids and fatty acids are trapped on a Bond-Elut C 18 column. Fluorescence (excitation and emission at 280 and 340 nm, respectively) is used for selective detection. The detection limit for indole and skatole is 15 gg kg- 1 back fat. The sample preparation procedure is simple and the method is sensitive and reproducible. - J. Chromatogr. 624, 479-490 (1992). Meat Res. Inst., DK-4000 Roskilde Determination of oil content in oilseeds by analytical supercritical fluid extraction. S.L. Taylor, J.W. King and G.R. List. Multiple quahtitative extractions with supercritical CO2 have been performed on several seed matrices. Experimental parameters were optimized to attain reproducible results. The supercritical fluid-based technique appears to be a suitable replacement for traditional extraction methods with organic solvents. - JAOCS 70, 437-439 (1993). Food Qual., Safety Res. Unit, Nat. Cent. Agricult. Utilization Res., Peoria, IL 61604 (USA) A multi-dimensional liquid chromatography method for determination of androgen hormone residues in cattle liver. G.W. Stubbings and M.J. Shepherd. A robust, reliable and sensitive HPLC system which can be easily automated is developed for the determination of trenbolone and 19nortestosterone steroid hormone residues in cattle liver. Sample extracts are defatted by size exclusion chromatography. The evaporated residue is injected onto a high performance gel permeation column and the two fractions containing the steroids are diverted onto individual silica concentration columns, where the hormone residues are retained. The trapped hormones are then determined separately. Trenbolone held on one concentration column is eluted onto a cyano HPLC column and the steroid peak from this is transferred onto a final analytical silica HPLC

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Particular matrices and fields of application

column. After reequilibration of the system the second concentration column is treated similarly for determination of 19-nortestosterone. Detection is by UV at 340 nm for trenbolone and 247 nm for 19nortestosterone. Detection limits in cattle liver are 0.1 gg/kg for trenbolone and 0.3 ~tg/kg for J 9-nortestosterone. For 2 Izg/kg, recoveries of 59% and 39%, with CVs of 7% and 10% were obtained for trenbolone and 19-nortestosterone, respectively. - J. Liquid Chromatogr. 16, 241 255 (1993). Min. Agric., Fisheries, Food, Colney, Norwich NR4 7UQ (GB)

Method I. Liquid chromatographic/fluorescence quantitative determination of albendazole residues in cattle liver. Method II. Gas chromatographic/mass spectrometric confirmatory method for albendazole residues in cattle liver. J. Markus and J. Sherma. Regulatory analytical methods for the residue determination of the anthelmintic drug albendazole in cattle liver are given. - J. AOAC Intern. 75, 1129-1137 (1992). U.S. Food Drug Admin., Dept. Health Human Serv., Cent. Vet. Med., Animal Drug Eval., Rockville, MD 20855 (USA) Determination of sulfadimethoxine, sulfamethoxazole, trimethoprim and their main metabolites in lung and edible tissues from pigs by multidimensional liquid chromatography. M.J.B. Mengelers, A.M.M. Polman, M.M.L. Aerts, H.A. Kuiper and A.S.J.P.A.M. van Miert. A multi-dimensional automated LC method combining aqueous gelpermeation on-line with trace enrichment and reversed-phase HPLC was developed in order to investigate the tissue distribution of sulfadimethoxine, sulfamethoxazole, trimethoprim and their main metabolites in lung tissue and edible tissues from pigs. Recoveries of parent compounds and their metabolites in spiked lung, muscle, kidney and liver tissue were constant and varied between tissues from 6 0 - 85%. Detection limits in these tissues were 1 0 - 5 0 ng/g tissue. - J. Liquid Chromatogr. 16, 257-278 (1993). State Inst. Quality Control Agricult. Prod., Dept. Toxicol., 6700 AE Wageningen (NL) Determination of tranquilisers and carazolol residues in animal tissue using high-performance liquid chromatography with electrochemical detection. M.D. Rose and G. Shearer. HPLC with electrochemical detection was applied to the multiresidue determination of acepromazine, azaperone, ehlorpromazine, haloperidol, propionylpromazine, xylazine, the metabolic of azaperone, azaperol and ~-adrenoreceptor blocking agent carazolol. The HPLC was carried out with a Hypersil SASC1 column using ammonium acetate solution/ acetonitrile (1:1) as mobile phase and a coulochem detector. The enhanced selectivity offered by the electrochemical detector allowed determination in liver extracts, which often give rise to more interferences on chromatographic traces when using conventional methods of detection. The method offers up to a ten-fold improvement in limits of determination over methods using ultraviolet and fluorescence detection. Recoveries and coefficients of variation have been determined in the range 2 - 2 5 gg/kg in pig kidney and liver. This electrochemical detection method has been used to measure residues in routine surveillance programmes. - J. Chromatogr. 624, 471 - 4 7 7 (1992). Min. Agricult. Fisheries, Food, Food Sci. Lab., Norwich NR4 7UQ (GB) Screening method for the quantitative determination of 12 sulfonamides in meat, liver and kidney by HPLC and on-line post-column derivatization. D. Guggisberg, A.E. Mooser and H. Koch. A screening method ist presented for the quantitative determination of 12 sulfonamide residues in different food tissues. Sulfabenzamide is used as internal standard and is added to the purified sample (10 g meat or 2 g other sample). The separation of the sulfonamides is achieved by reversed-phase HPLC on a Sperisorb ODS column with acetate buffer (pH 4.0)/acetonitrile (80:20) as mobile phase. The detection is carried out at 550 nm after post-column derivatization based on the Marshall Bratton method by diazotation with sodium nitrite and ammonium amidosulfonate and coupling with N-(l-naphthyl)ethylenediamine. Mitt. Gebiete Lebensm. Hyg. 84, 263--273 (1993). Bundesamt Veterinfirwesen, Sekt. Chem., CH-3097 Liebfeld-Bern (CH) Quantitation of cholesterol oxidation products in unirradiated and irradiated meats. K.T. Hwang and G. Maerker.

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A method to detect 7-ketocholesterol, cholesterol-5[3,6[3-epoxide, cholesterol-5c~,6e~-epoxide, 4-cholesten-3-one, 4,6-cholestadien-3-one and 4-cholestene-3,6-dione in unirradiated and irradiated beef, pork and veal was developed by use of chloroform-methanol-water extraction, solid-phase extraction, column separation, thin-layer chromatography and gas chromatography. This method recovered 78 - 88 % of the cholesterol oxidation products and detected the cholesterol oxidation products at 10 ppb or higher. A scheme for the isolation and quantitation of the cholesterol products in meats is given. - JAOCS 70, 371-375 (1993). East Reg. Res. Cent., Dept. Agricult. ARS, Philadelphia, PA 19118 (USA) A contribution to the identification of fatty acids from fish oils by massand FTIR-spectroscopy. J. Burhenne and H. Parlar. The identification of transesterified fatty acids from complex lipid mixtures by GC/MS and GC/FTIR is described. The degree ofunsaturation as well as the length of the carbon chain has been determined by the characteristical fragmentation of fatty acid methyl esters (FAME's) resulting from EI-MS and by the typical absorptions of FTIR-spectroscopy. - Fresenius Envir Bull 2,119 - 124 (1993). Dept. Anal. Chem., Univ. Kassel, W-3500 Kassel (D) Determination of methylmercury in fish samples using GC/AA and sodium tetraethylborate derivatization. R. Fischer, S. Rapsomanikis and M.O. Andreae. Methylmercury in fish tissue can be determined following simple dissolution in methanolic KOH solution, aqueous phase ethylation by derivatization with NaB(CzHs)4, cryogenic trapping on a packed chromatographic column, and GC separation, volatile mercury species are detected by AAS. Absolute detection limits are 4 pg of Hg for CH3Hg + and 75 pg of Hg for labile Hg 2÷. Concentration detection limits for this optimized procedure are 4 ng of Hg for CH3Hg + and 75 ng of rig for labile Hg 2 ÷ per gram of pulverized dried fish tissue. Analysis of standard reference materials demonstrates the accuracy, precision, and reproducibility of the analytical method. The clean-up procedure is characterized by separating the aqueous phase from the analyte gas stream hence avoiding sample handling and organic solvent extractions. - Anal. Chem. 65, 763-766 (1993). Biogeochem. Dept., Max Planck Inst. Chem., W-6500 Mainz (D) Ion exchange separation and pulsed amperometric detection for determination of biogenic amines in fish products. R. Draisci, S. Cavalli, L. Lucentini and A. Stacchini. An ion exchange chromatography method with integrated pulsed amperometric detection has been used for simultaneous determination of underivatized biogenic amines. The amines were extracted from fish products with a mixture of 5 % aqueous trichloroacetic acid, 6 mol/1 HC1 and n-heptane. The extract was passed through a C18 cartridge and the amines separated by cation exchange on an IonPac CS10 column using a gradient composed of acetonitrile/water/perchloric acid/sodium perchlorate. Detection was performed by integrated pulsed amperometry, and resulted in estimated detection limits of 5 ng for putrescine, 12 ng for cadaverine and histamine, and 25 ng for spermidine. The method was linear in the range 0.025 to 5 gg of injected amine. The average recoveries were greater than 92%. - Chromatographia 35, 584-590 (1993). Lab. Alimenti, Ist. Sup. Sanit/t, 00161 Rome (I) Detection of nitro musks in human milk and human fat. G. Rimkus and M. Wolf. Nitro musks - like musk xylene, musk ketone, musk ambrette, musk moskene, and musk tibetene - used as fragrances in cosmetic and detergent industry can be determined as residues in human milk and human fat samples by GC/ECD. The fat of the samples is extracted by the usual water/acetone/petrol partition method and subsequently cleaned-up by GPS and silica-gel adsorption chromatography. The residues were separated by GC on capillary columns (DB-5 and DB-1701) and identified by MS (EI and NCI). Best results were obtained in the SIM mode (GC/MS/NCI). Residues in the range of 0.02 to 0.22 mg could be detected. - Dtsch. Lebensmittel-Rundschau 89, 103-107 (1993). Lebensmittel-, Veterin. Unters. Amt Schleswig-Holstein, W-2350 Neumfinster (D)

209 A simple method for the determination of inorganic phosphate in milk. W. Reichardt and B. Eckert. To analyse inorganic phosphate in milk the molybdate/vanadate method is modified. The procedure is useful for measurements in the visible 315 nm range. The exact procedure is described in detail. Recovery rates of 9 5 - 9 8 % are obtained. The influence of different parameters on the occurence of inorganic phosphate in milk is investigated. Food 37, 7 9 - 8 1 (1993). Landwirtsch. Unters. und Forschungsanst. Thiiringen, Clausberg (D) Graphite-furnace atomic absorption spectrometric determination and survey of total aluminum, copper, manganese, molybdenum, and tin in infant formulas and evaporated milks. R.W. Dabeka and A.D. McKenzie. To determine A1, Cu, Mn, Mo and Sn in infant formulas and evaporated milks a GF-AAS method is described which is based on the 6 - 1 8 h dissolution of the samples in citric acid and HNO3 at 55°C. Digests were diluted to 10 ml with water and analyzed. Standards were prepared in a matrix of 30% HNO3 and 1% citric acid without digestion. Palladium (1 gg) was used as matrix modifier for aluminum and tin determinations. The mean detection limits of the method were 0.021, 0.043, 0.006, 0.063, and 0.073 gg/g for aluminum, copper, manganese, molybdenum, and tin, respectively. - J. AOAC Intern. 75, 954-963 (1992). Health and Welfare Canada, Health Protect. Branch, Food Res. Div., Bur. Chem. Safety, Food Direct., Ottawa, ON, K1A 0L2 (CDN) High performance liquid chromatographic determination of formaldehyde in milk. J. Kaminski, A.S. Atwal and S. Mahadevan. An HPLC procedure was developed for the determination of formaldehyde in milk. The analytical procedure consisted of the two-phase derivatization reaction with 2,4-dinitrophenylhydrazine and elution of formaldehyde-2,4-dinitrophenylhydrazone from Lichrosorb RP8 column with acetonitrile/water (2:3) as mobile phase and detection at 345 nm. In the range of 0.005 to 0.1 gg a linear calibration curve is obtained. The recovery is estimated to 89 to 97% at 0.1 and 1 gg/ml formaldehyde, respectively. The limit of detection is 0.0089 lag/m1. - J. Liquid Chromatogr. 16, 521-526 (1993). Cent. Food, Animal Res., Res. Branch, Agriculture Canada, Ottawa, Ontario K1A 0C6 (CDN) Capillary gas chromatography of some triglycerides in cheese using programmed-temperature injection. L. Alonso. A rapid gas chromatographic method with a TAP-CP coated WCOT capillary was used for the analysis of triglycerides in cheese with a programmed temperature vaporizer. Fat were extracted with hexane to dryness. The reproducibility of the method was assessed and the coefficient of variation for the total triglycerides was 2.50%. Recovery of individual triglycerides ranged between 87 to 105%. - Chromatographia 35, 649-652 (1993). Inst. Prod. L/tct., Asturias (E) Determination of protein-bound 2-amino-6-(2-formyl-l-pyrrolyl)-hexanoic acid (pyrraline) by ion exchange chromatography and photodiode array detection. T. Henle and H. Klostermeyer. Following enzymic hydrolysis, sensitive and unambiguous determination of the protein-bound Maillard compound pyrraline, a lysine derivative with a pyrrole structure, was achieved by ion-exchange chromatography with photodiode array measurement and subsequent ninhydrin detection. The method allows the simultaneous quantification of pyrraline in addition to the common amino acids, as well as acidlabile components such as the Amadori products and tryptophan, at levels lower than 500 gg/kg protein. - Z. Lebensm. Unters. Forsch. 196, 1 - 4 (1993). Lehrst. Milchwissensch., Techn. Univ. Miinchen, W8050 Freising-Weihenstephan (D) Polychlorinated biphenyl residues in food and human milk: determination of co-planar and mono-ortho substituted congeners. V. B6hm, E. Schulte and H.-P. Thier. An analytical method is described for determining the residues of coplanar as well as mono-ortho substituted PCB congeners both exhibiting toxicological relevance, in foods of animal origin and in human milk. The procedure, convenient for routine analyses, includes the extraction of lipids, clean-up steps using liquid/liquid partition and column chromatography, fractionation of the congeners using HPLC on a special

210 carbon column [Hypercarb (7 gm)] with an optimal gradient elution, and capillary column gas chromatography with electron capture or mass spectrometric detection. - Z. Lebensm. Unters. Forsch. 196, 435-440 (1993). Inst. Lebensmittelchem. Univ., W-4400 Mtinster (D) Contribution to oxidized cholesterol determination in milk and milk products. I. Possibilities and limits of RP-HPLC techniques. C. Sallin, E. Baumann, U. Biitikofer, R. Sieber and J.O. Bosset. Solid phase extraction on amino-phases, which provides milder conditions than saponification techniques, is used for the separation of oxidized cholesterols from milk and milk products. The separation of the oxidized cholesterols is carried out by RP-HPLC on Nucleosil C18 columns with acetonitrile/ethanol/water (80: 20:15-20) as mobile phase and UV detection using appropriate wavelengths. Six among 8 compounds are resoluted, 2 other compounds did not absorb at the chosen wavelengths. Linear calibration curves were obtained up to 0.2 mg/ml of organic extract. The detection limits are comparable to those indicated by S.K. B6singer [Dissertation, Wien 1991] (5 gg/ml) for cholestan213,5~-diol-6-on and ca. 1 gg/ml for the other compounds. Numerous interfering constituents and/or artefacts were observed in milk and milk products. - Mitt. Gebiete Lebensm. Hyg. 83, 141 - 1 5 7 (1993). Federal Stat. Milk Res., CH-3079 Liebefeld-Bern High-performance liquid chromatography-thermospray mass spectrometry of ten sulfonamide antibiotics. Analysis in milk at the ppb level. J. Abifin, M.I. Churchwell and W.A. Korfmachcr. Ten sulfonamide antibiotics including sulfanilamide (SNL), sulfamethazine (SMZ), sulfamethizole (SMTZ), sulfachloropyridazine and sulfaquinoxaline (SQX), were analyzed by thermospray (TSP) mass spectrometry on-line with HPLC/UV. Except for the pairs SMZ-SMTZ and sulfadimethoxine-SQX, the standards were resolved in both the UV and TSP profiles. Co-eluting compounds could be differentiated in TSP by their different relative molecular masses. TSP detection limits [signal-to noise ratio (S/N) < 3] were below 20 ng (scan mode), 2 ng (selected reaction monitoring, daughter ions from [M + H] +) and 400 pg (selected ion monitoring). UV detection limits were ca. 2 ng (S/N > 5). Results obtained from the multi-residue analysis of spiked cow milk samples at the low ng/ml level using a simple and rapid clean-up procedure are presented. - J. Chromatogr. 629, 267-276 (1993). US Food, Drug Admin., Nat. Cent. Toxicol. Res., Jefferson, AR 72079 (USA) Electrochemical detection of pyrroloquinofine quinone coupled with its catalytic function by liquid chromatography. Y. Esaka, K. Kano, M. Sukeguchi and M. Goto. An HPLC method with electrochemical detection is described for coenzyme pyrroloquinoline quinone (PQQ) which is based on its redox catalytic function. This catalytic reaction involves oxidative decarboxylation of glycine by PQQ and the reoxidation of the reduced PQQ by Fe(CN)63- to accumulate Fe(CN)64-, of which the electrochemical detection allows amplified detection of PQQ. Increase by two orders of magnitude of the current was achieved as compared with a direct reductive detection, at a reaction time of 3 rain and a reaction temperature of 25°C. The detection limit was 0.2 pmol (10 -8 M, 20 gl). The method was applied to quantification of PQQ in table vinegar, milk, and swine serum. - Anal. Sci. 9, 207-211 (1993). Gifu Pharm. Univ., MitahoraHigashi, Gifu 502 (J) On-fine SFE-GC for determination of PCBs in human milk and blood serum. H.R. Johansen, C. Thorstensen, T. Greibrokk and G. Becher. SFE-GC has been utilized for the determination of PCBs and other organochlorine compounds in human milk and blood serum. Preconcentration of the sample was performed on C18-silica sorbent in an extraction cell Proteins in milk are precipitated with acetonitrile before concentration whereas serum was applied to the C18 material without pretreatmerit. Basic alumina was utilized as a selective adsorbent for lipids in the on-line SFE-GC system. The method was used to analyze milk and serum spiked with 0.5 and 10 ng of Aroclor 1260 and the results compared with those obtained by liquid-liquid extraction of serum. - J. High Resol. Chromatogr. 16, 148-152 (1993). Dept. Chem., Univ., Blindern, 0315 Oslo (N)

2

Particular matrices and fields of application

HPLC receptorgram: A method for confirmation and identification of antimicrobial drugs by using liquid chromatography with microbial receptor assay. I. Sulfonamides in milk. E. Zomer, S. Saul and S.E. Charm. For confirmation, identification, and quantitation of 12 sulfonamide residues and p-aminobenzoic acid (PABA) in milk a method, termed "HPLC receptorgram", which uses liquid chromatography in conjunction with the microbial receptor assay (MRA) is used to monitor sulfonamides. The MRA for sulfonamies uses a microbial receptor and [SH]sulfamethazine tracer. Sulfonamides in milk bind to the receptor and inhibit the binding of the tracer to the receptor. Milk samples spiked at 10 ppb for each sulfonamide result in at least a 50% decrease in binding on the HPLC receptorgram. Additionally, milk samples spiked at the minimum detection level of the MRA assay can be confirmed, identified, and quantitated with coefficients of variation (%) of 7 . 6 - 24. Ten sulfonamides are determined with an isocratic buffer elution system containing 22% acetonitrile mobile phase, p-Aminobenzoic acid (PABA), an interfering sulfonamide analog, sulfanilamide, and sulfacetamide are eluted by using a 10% acetonitrile mobile phase. - J. AOAC Intern. 75, 987-993 (1992). Charm Sci., Malden, MA 02148 (USA) An improved method to measure glycomacropeptides (GMP) in renneted milk. S.K. Sharma, A.R. Hill and G.S. Mittal. An HPLC method was improved by using a gel permeation column (Protein Pak-125; 30 cm × 0.78 cm) to determine glycomacropeptides (GMP) during K-casein hydrolysis in the renneted milk. The modified method was more simple, efficient reproducible and required only 15 min compared to 40 rain required by an earlier method. The GMP peak was sharp, clean and was not overlapped by any background peak. The method could be used to study coagulation kinetics of ultrafiltered milk, to detect rennet whey solids in the skim milk powder and to determine the proteolytic activities of cheese enzymes. - Michwissenschaft 48, 7 1 - 7 3 (1993). Dept. Food Sci., Univ., Guelph, Ont. N1G 2WI (CDN) High-performance liquid chromatography of chemical hybridizing agent in wheat. F. Dardoize, N. Goasdoue, C. Goasdoue and R. Couffignal. Chemical hybridization agents (CHA) used for inducing pollen sterelity in economic crops can be determined by means of a simple HPLC method in grains, leaves, straw and glumes of traited wheat. The procedure included acido-basic extractions of wheat grains and tissues and derivatization of CHA residue as methyl ester compound. The chromatographic separation was achieved with Spherisorb silica using ethyl acetate-methanol (98:2) and UV detection at 285 nm. Good recoveries of CHA for fortified wheat grains and leaves were obtained. Recoveries of CHA in traited wheat demonstrated accumulation of the agent in reproductive organs. - J. Liquid Chromatogr. 16, 1517-1528 (1993). Lab. Chim. Mbd. Mol., Univ. Pierre et Marie Curie, F-75252 Paris Cedex (F) Polarographic determination of total pyrethroid residues in stored cereals. G. Corbini, C. Biondi, D. Proietti, E. Dreassi and P. Corti. Cyanopyrethroids in stored cerials were extracted with a; non-polar solvent and purified by solid-phase extraction. The total pyrethroid residue concentrations are determined by differential-pulse polarography of 3-phenoxybenzaldehyde formed quantitatively by rapid and reproducible alkaline alcoholysis of the sample. The method is linear, quantitative and reproducible for maize and wheat analysis in the range 0.1 - 3 . 0 mg kg-1. A thin-layer chromatographic method on a silica gel 60 plate with cyclohexane/chloroform/methanol (6:1:0.1) for identification of six widely used cyanopyrethroids is described. The electronic reduction process of 3-phenoxybenzaldehyde is examined and the reduction products isolated and identified. - Analyst 118, 183-187 (1993). Dipt. Farm. China. Techn., Univ., Siena (I) Comparison of GC and HPIC methods for the analysis of saccharides. C.D. Patz, E. Zimmer and H. Dietrich. The determination of sugar monomers from fruit hydrocolloids by GC and HPIC is compared. The colloids arc hydrolysed with trifiuoroacetic acid or sulfuric acid. The saccharides arc then analyzed by GC as alditolacetates on a SP2330 film capillary with a temperature program from 190 to 240°C or by HPIC on an anion-exchanger column

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Foods

with amperometric detection and isocratic elution with NaOH and sodium acetate for the neutral sugars and the uronic acids, respectively. A gradient program for the separation of the neutral sugars is included. Both methods are suitable for the determination of the sugar monomers. Comparable results are obtained. Higher recoveries are obtained with the hydrolysis by sulfuric acid. Due to the derivatization step for the GC-analysis higher results are obtained with HPIC. With the GC methods better results are obtained for the different sugar compounds, but the HPIC-method is simpler and does not need so many solvents. Dtsch. Lebensm. Rundsch. 89, 1 - 6 (1993). Forsch. Anst. Geisenheim, W-6222 Geisenheim (D)

High-performance liquid chromatographic determination of polyamines in selected vegetables with postcolumn fluorimetric derivatization. H. Ohta, Y. Takeda, K.-I. Yoza and Y. Nogata. Agmatine, putrescine, cadaverine, spermidine and spermine can be separated by HPLC after postcolumn derivatization with o-phthalaldehyde on a strong cation-exchange column with an elution buffer consisting of 1 M sodium citrate (pH 5.4), a mixing coil for the chemical reaction and a spectrofluorimetric detector. The derivatized fluorescent compounds were detected at 340/455 nm. The recoveries of the polyamines were 94.5-107.0% with a standard deviation of 0.83-7.65%. - J. Chromatogr. 628, 199-204 (1993). Chugoku Nat. Agricult. Exp. Stat. Ministry Agricult., Forestry, Fisheries, Fukuyama City, Hiroshima 721

Nitrate determination in plant, mushroom and algae species using an ionselective electrode. H. Kolbe, W.-L. Zhang, H. Schfirer, T. Wathsack and U. K/insch. The nitrate contents of dry powder from 55 different plant, mushroom and algae species were determined by means of an ion-selectiveelectrode. Different extraction media as water, 1% copper sulfate, 1% and 5% potassium aluminium sulfate were tested with different sample quantities. Increasing amounts of 0.9 M aluminium sulfate or 0.01 M silver sulfate were added to the sample extracts in order to adjust the ionic strength. The nitrate content was measured after every addition. Samples of leaves or needles from trees require the addition of poly(vinyl)poly(pyrrolidone) to the extractant probably to remove phenolic compounds. Detailed analytical procedures for the nitrate determination are given. The obtained nitrate values are in good accordance with those obtained by the Cd reduction and bacteriological methods. In samples with less than 150 mg/kg dry mass with all methods a considerable variance can be seen. - Agribiol. Res. 46, 8 9 - 99 (1993). Inst. Agricult. Chem., Univ., W-3400 Gtttingen (D)

(J)

A simple and quick gas chromatographic method for the determination of propham and chlorpropham in potatoes. H. Beernaert and P. Hucorne. A GC method is developed for the quantitative determination of residual propham and chlorpropham in potatoes. Both herbicides are extracted from the foodstuff with methylene chloride. After centrifugation and concentration, propham and chlorpropham are quantitatively determined by gas chromatography thermionic detection using a fused silica capillary column CP Sil 5CB. 2-Choroaniline is used as internal standard. Recoveries of 100 _+ 15% and 99 ± 10% have been obtained for propham and chlorpropham in blank samples spiked. The absolute detection limit for both compounds is I n g corresponding to 0.1 rag/ kg. Z. Lebensm. Unters. Forsch. 193, 433-435 (199I). Inst. Hyg. Epid., Food Div., B-1050 Brussels (B) Determination of folic acid contents in vegetables and fruits by means of high-performance liquid chromatography (HPLC). H. Mtiller. The folic acid content of vegetables (including potatoes) and fruits was determined by means of HPLC according to J.F. Gregory III, D.B. Sartain and B.P.F. Day [J. Nutrit. 114, 341 (1984)]. In addition, the results of the quantification of the main folate derivatives tetrahydrofolic acid, 5-methyltetrahydrofolic acid and 5-formyltetrahydrofolic acid are presented. Their total, resulting from the addition of pteroylglutamate equivalences, is comparable with the results of microbiological methods reported in the tables of nutritive values. - Z. Lebensm. Unters. Forseh. 196, 137-141 (1993). Inst. Ern/ihr.phys. der BFA fiir Ern/ihrung, W7500 Karlsruhe I (D) Determination of 3-chloropropane-l,2-diol in hydrolyzed vegetable proteins by capillary gas chromatography with electrolytic conductivity detection. G. Spyres. 3-Chloropropane-l,2-diol in hydrolyzed vegetable protein can be determined using capillary GC with an electrolytic conductivity detector operated in the halogen mode. The hydrolysate is absorbed onto a Extrelut QE column of kieselguhr, 3-chloropropane-l,2-diol is partitioned into ethyl acetate and is quantitatively measured by gas chromatography using l-chlorotetradecane as the internal standard. A concentration of 1 mg/kg dry substance is easily determined. The halogen-specific detector provides sample chromatograms free from interfering peaks. - J. Chromatogr. 638, 7 1 - 7 4 (1993). A.E. Staley Manufact. Co., Decatur, IL 62525 (USA)

Determination of cobalt, molybdenum and vanadium in Austrian mineral waters by ICP-AES after ion-exchange separation and preconcentration. I. Steffan and G. Vujicic. Co, Mo, and V can be determined in mineral water samples by ICPAES after separation of these elements from the matrix by ion exchange. The samples are acidified with concentrated HC1 (10 ml/1) and the elements are adsorbed as thiocyanate complexes. Elution is performed with a mixture 2 M in perchloric acid and 1 M in HC1 and subsequently with 1 M HC1. After evaporation of the eluates and dissolution of the residue the volume of the measuring solution for ICP-AES is 10 ml. The recoveries for Co, Mo and V at a concentration level of 1 gg/1 in mineral waters were approximately 99%. A concentration factor of 100 is achieved by this procedure. - Mikrochim. Acta 110, 8 9 - 9 4 (1993). Inst. Anal. Chem., Univ. Vienna, A-1090 Wien (A) Simultaneous determination of organic acids and cations in beverages by ion chromatography with a single elnent using a column switching technique. M. Ding, Y. Suzuki and H. Koizumi. The column switching method was applied to the separation of organic acids and cations in beverages by ion chromatography. A cation exchange column (Yokogawa ICS-C25) and an anion exchange column (Yokogawa SAM3-075) were connected in series. A column switching program is described, The chromatograms for anions and cations can be recorded on a single chart with only one sample injection. Organic acids and five cations were separated at ambient temperature within 60 rain when 1.5 mM oxalic acid at a flow rate of 0.75 ml/min was used as an eluent. The proposed method was applied to simultaneous determination of both organic acids and cations in wine, juice and coffee with good reproducibilities. Bunseki Kagakn 42, 4 9 - 5 4 (1993); (Orig. Jap.) Dept. Chem. and Biotechn., Fac. Engin., Yamanashi Univ., 4-311 Takeda, Kofu-shi, Yamanashi 400 (J) High-performance liquid chromatographic determination of sugars in an infusion and soft drinks using a silica-based 3-morpholinopropyl-bonded stationary phase. S. Akiyama, K. Nakashima and K. Yamada. 3-Morpholinopropylsilyl-modified silica gel (MPS) was successfully applied to the HPLC-separation of many kinds of sugars (rhamnose, xylose, arabitol, glucose, mannose, sucrose, maltose, melibiose, raffinose and maltotriose) and the determination of glucose or/and sucrose in an infusion, drinks for sports and soft drinks, with elution with acetonitrile10 mM imidazole-borate buffer (pH 6.5) (90:10, v/v) by refractive index detection. The MPS column was found to be chemically stable under the elution conditions used and during continuous operation for over 500 h. The calibration line for glucose in soft drinks was linear over the range 62.5-500 nmol. - J. Chromatogr. 626, 266-270 (1992). School Pharm. Sci., Univ., Nagasaki 852 (J) Quantitative changes of phenolic components during extraction of apple and pear juices. K. Hernnanu. Difficulties encountered with the quantitative determination of phenolic compounds in apple and pear juices are reviewed. It seems to be useful to determine the total content of phenols in the juice before complicated determinations of the single components will be carried out. Some of the phenolic compounds are extremely labil and easy to oxidize so that it is important to avoid oxidizing conditions during analysis. Factors influencing the contents of phenols in juices during the juice production and during its storage are discussed. Problems encountered

212 with the different distribution of phenolic compounds in different fruits are mentioned as well. - Fliissiges Obst 60, 7--10 (1993). Inst. Lebensmittelchem., W-3000 Hannover (D) R.H.S.

Determination of dinocap in apples, grapes, and pears using a solid phase extraction cleanup and HPLC-UV detection. F.J. Schenck and M.K. Hennessy. An SPE technique on Bond Elut C-18 for the isolation and HPLCUV determination of the pesticide dinocap in apples, grapes and pears is described. Samples are extracted with acetone; the acetone extract is subjected to cleanup on both C-18 and silica SPE columns. The residues are determined using HPLC on an ODS-column with acetonitrile/water (60:40 or 56:44) with UV detection at 245 nm. The average recovery from crop samples spiked at tolerance, 0.1 ppm dinocap, was 85.9%. J. Liquid Chromatogr. 16, 755-766 (1993). Food Drug Adm., Baltimore, MD 21201 (USA) Analysis of phenolic and flavonoid compounds in juice beverages using high-performance liquid chromatography with couiometric array detection. P. Gamache, E. Ryan and I.N. Acworth. Analysis of phenolics and flavonoids in juice beverages using reversedphase HPLC with coulometric array detection is described. A binary gradient elution with 0.1 M NaHzPO4 + 10 rag/1 SDS (pH 3.35) and acetonitrile/0.1 M NaH2PO4 + 50 rag/1 SDS/methanol (60: 30:10) (pH 3.45) was used for the separation. Sixteen serial coulometric detectors were used for on-line resolution ofco-eluting compounds and generation of voltammetric data. Within each class of compounds, oxidation potential corresponded to specific substitution patterns where: catechol < methoxycatechol < monohydroxyl < methoxyl. Twenty-seven standard compounds were resolved in a 45-rain run. The limits of detection were in the low ng/ml range with a linear response range of at least three orders of magnitude. Intra-run retention time variation was < 1% (R.S.D.) and adjacent sensor response ratios varied by < 5% (R.S.D.). The utility of this technique in generating multivariate data for differentiation of juices and juice mixtures is shown. - J. Chromatogr. 635, 143-150 (1993). ESA Inc., Bedford, MA 01730 (USA) Determination of methyl anthranilate and methyl N-methylanthranilate in beverages by liquid chromatography with fluorescence detection. P. Vifias, C. L6pez Erroz and M. Hernfindez C6rdoba. A reversed phase HPLC method for the separation and determination of two anthranilic acid derivative esters, methylanthranilate and methyl N-methylanthranilate, has been developed. A gradient elution technique, using methanol/water changing from 40:60 to 80:20 mixtures, is used. The sensitivity of the determination is improved by using fluorescence detection. The proposed method is applied to the determination of the esters in wines, brandies, grape beverages and fruit juices. Chromatographia 35, 681 - 6 8 4 (1993). Dept. Anal. Chem., Fac. Chem., Univ., 30071 Murcia (E) Determination of patulin by reversed-phase high-performance liquid chromatography with extraction by diphasic dialysis. J. Prieta, M.A. Moreno, J. Bayo, S. Diaz, G. Sufirez, Lucas Dominguez, R. Canela and V. Sanchis. A simple and economical method has been developed for the determination of the mycotoxin patulin in apple juice. The sample is extracted with ethyl acetate in a diphasic dialysis system, and the extract is cleaned up by elution from a Sep-Pak cartridge. Patulin is detected and determined by reversed-phase HPLC using a Novapak C18 column with water/THF (99:1) as mobile phase and UV detection at 275 nm. The lower detection limit is 1 p.g 1-1 and the recovery is 85% at the 20 gg 1-1 level. - Analyst 118, 171--173 (1993). Dept. Patol Animal, Fac. Veterin., Univ. Complutense, E-28040 Madrid Determination of small amount of lactone by a supercritical fluid FIA with chemiluminescent detection. M. Ishii and M. Koike. By using a CO2 supercritical fluid (SCF) as FIA carrier and chemiluminescent (CL) reaction medium, an SCF-FIA/CL system was developed in order to determine small amount of lactone. Lactone reacts with sodium hydroxide and sodium hydroxide/ethanol, and changes to oxycarboxylic acid and giycolic acid ester, respectively. These two

2 Particular matrices and fields of application compounds react with each other, and the diester is finally produced. The diester reacts with dissolved oxygen, and a hypercompound, such as peroxide of oxalic acid diester is produced. The exited compound being a CL emitter produces the CL and the CL is enhanced in SCF. Analytical characteristics for 7-butyrolactone (7-BuLac) as a representative were as follows. Lower detection limit: 1.0 × 10 1° M (20 pl injection method: S/N = 2). Lineality of the calibration: 1.0 x 10- 9 1.0 )< l 0- 7 M. Selectivity: excellent to lactone. Reproducibility: 5.5% in terms of relative standard deviation (5 repeated runs for 1 x 10 8 M 7-BuLac in 20 pl injection volume). Analytical time required: ca. 3 s. Recovery test for 7-BuLac in coffee essence was successfully achieved. - Bunseki Kagaku 42, 173 - 181 (1993); (Orig. Jap.) Dept. Ind. Chem., School Sci. Techn., Meiji Univ., Kawasaki-shi, Kanagawa 214 (J) ~

Sample stacking effects and large injection volumes in micellar electrokinetic chromatography of ionic compounds: Direct determination of iso-~-acids in beer. R. Sziics, J. Vindevogel, P. Sandra and L.C. Verhagen. Sample stacking can be performed in MEKC of ionic compounds. To obtain favorable conductivity ratio between a beer sample and background electrolyte increasing separation buffer concentration has to be used. If this ratio is well controlled, larger injection volumes can be used. The direct analysis of iso-~-acids in beer, thus omitting prior extraction, is demonstrated. Data on quantitative analysis are presented. Chromatographia 36, 323-329 (1993). Lab. Organ. Chem.i Univ., B9000 Gent (B) Application of continuous flow analysis technology for quality control in the brewery industry. Part IV: Determination of the content of free amino nitrogen in wort and beer. B. Baier, M. Liick, J. Harms, O. Miicke and E. Kriiger. A continuous flow analysis (CFA) method is presented for the determination of free amino nitrogen in wort and beer. By means of statistical methods to DIN 38402 Part 7 it is shown that the automated method is comparable to the ninhydrin method by MEBAK [Methodensammlung der mitteleurop/iischen brautechnischen Analysenkommission, Band 1, 189-191 (1985)]. The application of the CFA-method leads to an improvement in the reproducibility of the measured results and to a reduction in time and costs. - Brauwissenschaft 46, 223-229 (1993). Fachb. Lebensmitteltechnol., Humboldt-Univ., O-1040 Berlin (D) Screening method for the detection of maize in beer. R. Pfitzold, R. Fenz, M. Krause and R. Galensa. A HPLC method is described, which allows a quick decision about the use of maize as a maltsurrogate in brewing process. Indicator is lO-trans-p-coumaroylglycerol. For clean-up, a double step solid phase extraction with RP-18 and ion exchange-cartridges is used. The HPLC separation is carried out with [3-cyclodextrin columns using a gradient from 30-100% methanol in methanol/water/acetic acid (1:9 : 5). The detection is carried out at 310 nm. - Dtsch. Lebensm. Rundsch. 88, 390-391 (1992). Inst. Lebensm.chem., TU Braunschweig, W-3300 Braunschweig (D) Ammonium determination in wine by gas phase molecular absorption spectrometry. J. Sanz, S. de Marcos, O. Muro and J. Galbfin. A procedure for the determination of ammonium is described, based on its transformation into ammonia gas and subsequent measurement by UV-visible molecular absorption spectrometry at 194 nm. Two different procedures for generating the ammonia are proposed, using NaOH solution and solid NaOH, respectively. After generation conditions for both procedures had been optimized, better sensitivity was observed with solid NaOH. The method showed two ranges of linear response: from 1 to 100 gg and from 100 to 400 gg of ammonium. After elimination of ethanol by vacuum evaporation of the sample ammonium can be determined in wine by means of this method. The recovery of ammonium added to the wine samples was around 95%. - Mikrochim. Acta 110, 193--204 (1993). Anal. Chem. Dept., Univ. La Rioja, Obispo Bustamante 3, E-26001 Logrofio (E) A simple method for the determination of lead in wine using Zeeman electrothermal atomization atomic absorption spectrometry. M.R. Matthews and P.J. Parsons.

2.5

213

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A simple method for the determination of lead in wine by EA-AAS is described. Lead is measured following a simple 1:4 dilution of wine samples with a chemical modifier solution containing 0.25% HNO3, 0.25% NH4H2PO4, and 0.0125% Mg(NO3)2. Instrument calibration is carried out using six Pb standard solutions. Using the optimized furnace conditions, the characteristic mass (too) is 41.7 pg (expected mo = 33 pg). Overall precision is good (RSD _< 5.0%) and the minimum detection limit (3~) for Pb in wine is 6.2 gg/1. The accuracy of the method is assessed. At. Spectrosc. 14, 4 1 - 4 5 (1993). Dept. Environ. Health Toxicol., School Public Health, Univ., Albany, NY 12237 (USA)

HPLC. The feed is extracted with aqueous oxalic acid (pH 2.7), cleaned over a benzenesulfonylpropyl-silicagel or a propylsulfonyl-silicagel (nicotinamide) cation exchange column, which is washed with water and eluted with KH2PO4 solution (pH 7.3). The cleaned extract is analysed on a Nucleosil C18 column with KHzPO4 (pH 4.5) and KH2PO4 (pH 2.5)/acetonitrile (99:1) for nicotinic acid and nicotinamide, respectively, and detected at 264 nm in UV. Recovery rates of 97.4% to 101.2% and 95.3% to 102.7% were found for nicotinic acid and nicotinamide, respectively. The limit of determination is 5 ppm, the loss of nicotinamide during pelleting is lower than 10%. - Agribiol. Res. 46, 1 0 - 1 9 (1993). Ind. Fine Chem. Div., Appl. Technoi., Feed Additives, W-6450 Hanau

Determination of lead and aluminium in port wine by electrothermal atomic absorption spectrometry. A.A. Almeida, M. Lourdes Bastos, M.I. Cardoso, M.A. Ferreira, J.L.F.C. Lima and M.E. Soares. Pb and A1 can be determined in port wine by ET-AAS based on the stabilized temperature platform furnace concept. Except for the dilution step, no sample preparation was required. The determinations were performed in the linear range 1.9-100 gg 1-1 for lead and 1 . 6 - 50 gg 1-~ for aluminium in the port wine samples, after appropriate dilution (usually 1 + 9 for lead and 1 + 24 for aluminium). These correspond to detection limits of 19 and 40 gg 1-1 for lead and aluminium, respectively, in undiluted samples. The precision was better than 4% (at a concentration level of about 25 gg l -z) for lead and 3% (at a concentration level of about 35 gg 1 2) for aluminium. The simplicity and rapidity of each analysis (a graphite furnace programme time of 159 s for lead and 85 s for aluminium) makes this method most attractive for routine analysis. - J. Anal. At. Spectrom. 7, 1281-1285 (1992). Fac. Pharm., Univ., P-4000 Porto

(D)

HPLC determination of volatile phenols in wines. J. Siegrist, C. Salles and P. Eti~vant. The quantification of ethyl- and vinylphenols and ethyl- and vinylguaiacols in wines can alternatively be carried out using AG2-X8 as anion exchange resin. The percolation of clarified wine adjusted to pH 9 on this resin permits, in particular, the elimination of organic acids. Phenols are not eluted after rinsing the column with 1N HC1, but are eluted with methanol after this treatment. Good recovery (91%) and good repeatability are observed. The eluate is directly analysed by HPLC on an RP18 column after two-fold dilution in water. The four volatile phenols were completely separated and detected by UV at 280 nm with high sensitivity (20-40 ppb). No interference with other compounds were noted in the different wines analysed. - Chromatographia 35, 5 0 - 5 4 (1993). Lab. Recherch. Ar6m., INRA, 21034 Dijon Cedex (F) Methods for fast analysis of anthocyanins and anthocyanidins in red wine. K. Datzberger, I. Steiner, J. WashfittI and G. Kroyer. Analytical methods for the identification and quantification of the different anthocyans and anthocyanins in red and ros6 wine have been developed. The photometric, column chromatographic, high-performance liquid chromatographic and high-performance thin-layer chromatographic methods can be easily used for screening wine colours. - Z. Lebensm. Unters. Forsch. 193, 462 464 (1991). Inst. Food Chem. Technol., Techn. Univ. Vienna, A-1060 Vienna (A)

Identification of flavonoids by TLC scanning analysis. S. Garcia, H. Heinzen, R. Martinez and P. Moyna. Flavonoids can be determined directly by densitometry on TLC-plates. UV spectra can be measured directly on the developed plates without previous elution. Results are comparable to those obtained with classical methods. As the isolation step can be avoided results can be observed with 100 ng samples. - Chromatographia 35, 430-434 (1993). Fac. Quim., Univ. Rep., Casilla de Correo 1157, Montevideo (U) Flow-injection chemiluminometric determination of sodium cyclamate. I.M. Psareliis, E.G. Sarantonis and A.C. Calokerinos. Sodium cyclamate can be determined by its sensitizing action on the cerium(IV)/sulphite chemiluminescent reaction. The flow-injection method developed is rapid and precise and allows measurements in the range 1.00-50.0 gg ml- ~ on up to 100 solutions per hour. Acetonitrile does not alter significantly the analytical characteristics of the method, which can therefore be proposed for the determination of the analyte after liquid chromatographic separation from other sweeteners and possible metabolites. - Anal. Chim. Acta 272, 265 - 270 (1993). Lab. Anal. Chem., Univ., 15771 Athens (GR) Use of solid phase extraction in the HPLC determination of artificial sweeteners in food. M. Lehr and W. Schmid. Interferences due to food compounds during the isocratic HPLCdetermination of artificial sweeteners saccharin, acesulfame and aspartame can be eliminated by extraction on SPE-columns. Different SPE-columns were tested. Recovery rates of about 90% were obtained with amino anion-exchange and octadecyl columns, respectively. In the case of the investigated food samples the HPLC determination of cyclamate after conversion to N,N-dichlorocyclohexylamineis not interfered by other food compounds. - Dtsch. Lebensmittel. Rdsch. 89, 4 3 - 4 5 (1993). Inst. Pharm. Lebensmittelchem., Ludwig-MaximiliansUniv., W-8000 Mfinchen 2 (D)

2.5 Gas chromatographic determination of sugars and polyalcohols in apple liqueurs. L. Co11 Hellin, L. Guti~rrez Ruiz and A. Zapata Revilla. A GC-method to determine sugars and polyalcohols in apple liqueurs is proposed. The sugars were determined as trimethylsilyl derivates. This technique enables isolation of the :¢ and 13anomeric forms of fructose, glucose and maltose. The precision and accuracy of the method has been verified. The liqueurs analysed are sweet liqueurs, as can be deduced from their high sugar content (over 100 g/l). Reducing sugars (glucose and fructose) were predominant. - Z. Lebensm. Unters. Forsch. 196, 4 9 - 5 2 (1993). Dept. Bromatol., T~cn. Anal. Farm., Fac. Farm., Univ. Complutense, E-28040 Madrid Determination of supplemented nicotinic acid or nicotinamide in compound feed by HPLC after cleaning of the feed extract with cationic sorbent extraction. J. Fontaine and J. H6rr. Both forms of vitamin B3, nicotinic acid and nictoninamide, which are used to supplement compound feed can be determined separately by

Pharmaceutical analysis

Reproducible and high-speed separation of basic drugs by capillary zone electrophoresis. G.L. Chee and T.S.M. Wan. The complete separation of a mixture of seventeen basic drugs of different classes was achieved with capillary zone electrophoresis in 11 rain. 0.05 M phosphate buffer (pH 2.35) was used as running buffer. A constant voltage was used. The migration time reproducibility for individual components was between 0.5 and 1.7% relative standard deviation (R.S.D.). Peak detection was achieved by ultraviolet absorption, with peak-area reproducibility ranging from 1.5 to 6.3% R.S.D. The pH of the running buffer was critical in determining the separation of the mixture of basic drugs. The detection of most of these components in urine and plasma is also illustrated. An extraction step with chloroform/isopropanoI (9:1) is necessary for clinical samples. - J. Chromatogr. 612, 172-177 (1993). Dept. Chem., Hong Kong Univ. Sci. Technol., Clear Water Bay, Kowloon (HK)

214 Applications of capillary eleetrophoresis in the pharmaceutical industry.

2 Particular matrices and fields of application

M. Parker and J. Chapman. HPLC and high-performancecapillary electrophoresis are ideal complementary techniques which both can be automated. High resolution separations can be obtained with fast analysis times (less than 30 rain) while each technique retains its own unique mechanism of separation. Examples for capillary electrophoresis in pharmaceutical industry are given, especially micellar electrokinetic capillary chromatography (MECC) of pharmaceutical preparations, nucleic acids and analogs, opiates by MECC, drug metabolites and chiral separation. - European Chromatogr. Anal. 5, 9--11 (1993). Beckman Instruments, High Wycombe (GB)

N,N'-l,2-ethylenediylbis(cysteine) diethylester, the single L,Lenantiomer, is the active ingredient in Neurolite, a technetium based agent for single-photon emission computer tomography brain imaging. A unique cyclodextrin-based chiral separation is presented for enantiomers which do not fit the commonly held selection criteria for chiral separations. The enantiomers of N,N'-l,2-ethylenediylbis(cysteine), diethyl ester are separated as the analogous rhenium(V)oxo complexes using a Cyclobond II column and a methanol-water mobile phase. The rigidity added to the molecule via the formation of the metal complex is sufficient to replace the normal requirement for an aromatic ring in the molecule for successful separation. - J. Chromatogr. 635, 203 - 2 0 9 (1993). DuPont Merck Pham. Co., North Billerica, MA 01862 (USA)

Use of computer simulations in the development of gradient and isocratic high-performance liquid chromatography methods for analysis of drug compounds and synthetic intermediates. L. Wrisley.

Inhibition of growth of calcium oxalate crystals at constant supersaturation: determination of phytate. F. Grases, A. Costa-Bauzfi and J.G.

The computer simulation programs Dry/Lab G/plus and DryLab I/ plus are used for optimization of gradient and isocratic HPLC conditions for the assay of drug substances and related compounds. Data obtained after two experimental runs in the laboratory are entered into the appropriate program where HPLC conditions can be altered (e.g. flow-rate, column dimensions, mobile phase composition, gradient steepness and shape, etc.) to arrive at optimum separation conditions with less analyst time required. The computer simulations from DryLab G/plus are shown to be suitably accurate under "real life" conditions. - J. Chromatogr. 628, 191-198 (1993). Anal. Res., Serv., Wyeth-Ayerst Lab., Rouses Point, NY 12919 (USA)

Self-assembled monolayers in electroanalytical chemistry: Application of o~-mercapto carboxylic acid monolayers for the electrochemical detection of dopamine in the presence of a high concentration of ascorbic acid. F. Malem and D. Mandler. A novel approach for the use of self-assembled monolayers in electroanalytical analysis is described. Self-assembled monolayers of mmercapto carboxylic acids, HS(CH2)nCO2H (n = 2, 5, 10), C,, on gold electrodes were used as a means to induce electrochemical differentiation between a neurotransmitter, dopamine, and ascorbic acid. Optimum differentiation is found for n = 5, and it is attributed to a compromise between a well-organized system that requires long m-mercapto carboxylic acids and a reasonable rate of electron transfer which is observed with short m-mercapto carboxylic acids. - Anal. Chem. 65, 37-41 (1993). Dept. Inorg. Anal. Chem., Univ., Jerusalem 91904 (IL)

The on-line determination of the enantiomeric purity of enzymaticaHy produced chiral compounds. T. Alebic-Kolbah, G. F61ix and I.W. Wainer. To determine the enantiomeric purity of enzymatically produced chiral compounds an immobilized enzyme HPLC reactor based upon ~chymotrypsin (ACHT-IMER) was linked through a switching valve to a chromatographic column containing a crown ether-based chiral stationary phase (CR-CSP). This configuration is a model for other IMER/CSP coupled-column systems which can be used for analytical and preparative applications. - Chromatographia 35, 264-268 (1993). McGill Univ., Dept. Oncol., Pharm.kin. Div., Gen. Hosp., Montreal, PQ, H3G 1A4 (CDN)

Evaluation of series-coupled gas chromatographic capillaries of different polarities. Application to the resolution of problem pairs of constituents in Algerian cypress essential oil. N. Chanegriha and A. Baaliouamer. Two WCOT fused-silica columns with grafted phases, a low-polar CPSil 5 CB column and a high-polar CP-Wax 57 CB capillary were coupled in series. By changing the temperature programme gradient or the column sequence, an efficient separation system is obtained. Retention indices of some previously unresolved constituent pairs were calculated and an application to the analysis of cypress essential oil is reported. J. Chromatogr. 633, 163-168 (1993). Univ. Sci. Technol., Inst. Chim., Lab. Anal. Org. Fonct., Bab-Ezzouar, Algiers (Algeria)

Liquid chromatographic separation of radiopharmaceutical ligand enantiomers. J.M. Green, R. Jones, R.D. Harrison, D.S. Edwards and J.L. Glajch.

March. An odd method for the determination of phytate is presented which is based on the effective kinetic inhibitory effect on the growth rate of crystals of calcium oxalate during supersaturation. In the concentration range of 13 - 120 nM phytate the logarithm of the slope decrement was a linear function, the detection limit of phytate being 3 nM. The rel. standard deviation (n = 10) in the 90 nM range was 0.8%. - Analusis 21, 9 5 - 9 9 (1993). Dept. Chem., Univ., 07071 Palma de Mallorca (E)

Liquid chromatographic purification and detection of anabolic compounds. L.A. van Ginkel, E.H.J.M. Jansen, R.W. Stephany, P.W. Zoontjes, P.L.W.J. Schwillens, H.J. van Rossum and T. Visser. The role of liquid chromatography within methods of analysis for steroids, related compounds and [3-agonists in biological samples is reviewed concerning 29 references. Special attention is given to the application of liquid chromatography in sample preparation and extract clean-up. Different forms of liquid chromatography, including immunoaffinity chromatography, are compared and evaluated. Methods for confirmation based on gas chromatography-mass spectrometry and cryotrapping Fourier transform infrared spectrometry are discussed. J. Chromatogr. 624, 389-401 (1992). Lab. Residue Anal., Nat. Inst. Public Health, Environ. Protect., 3720 BA Bilthoven (NL)

Development of a radioimmunoassay for the determination of buprcnorphine in biological samples. L. Debrabandere, M. Van Boven and P. Daenens. A specific and sensitive radioimmunoassay for the detection of buprenorphine in urine and in plama samples is described. The 2-diazobenzoic acid derivative of buprenorphine has been prepared as a hapten. The immunization of rabbits with the hapten-bovine serum albumin conjugate resulted in the production of antibodies, which cross-reacted with N-dialkylbuprenorphine up to about the 90% level. The antibodies showed very low cross-reactivities with the 3-O-glucuronides and with the structural analogue etorphine. Intra- and inter-assay relative standard deviations were < 4.35 and < 6.36%, respectively. The minimum detectable dose of the immunoassay was calculated to be 10 pg ml(Student's t-distribution, p = 0.01, degrees of freedom = 8). A comparison with an HPLC method was carried out. - Analyst 118, 137-143 (1993). Lab. Toxicol., Univ. Louvain (KULeuven) B-3000 Leuven

Analysis of antiepileptic drugs in serum: Fully automated preparation with the LichroGraph OSP-2. U. Jiirgens. A fully automated method for the anti-epileptic drug monitoring in serum samples is described. On the basis of direct sample injection with pre-column switching, the method was developed by adapting the OSP-2(On-Line Sample Preparator) for routine determination. Serum samples (unprepared or diluted with an internal standard solution) were injected onto 4 x 4 mm cartridges filled with 25 ~m C-18 material. After the washing step the OSP-2 transfers the cartridge to a second holder position where it is eluted by the mobile phase for subsequent gradient separation. The main difference between a "tandem" column switching device with two alternateiy switched 6-port valves and the OSP-2 is that in the latter apparatus the pre-column cartridge is automatically changed after every sample injection. The system is applied to a serum sample with carbamazepine, phenobarbital and phenytoin. - Kontakte (Darm-

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215

stadt) 3, 2 9 - 3 5 (1992). Gesellschaft fiir Epilepsieforschung, Biochem. Lab. Bethei, W-4800 Bielefeld 13 (D)

216 (1993). Fac. Pharm. Sci., Kyushu Univ. 62, Maidashi, Higashi, Fukuoka 812 (J)

Determination of phenolic antioxidants in pharmaceutical formulations by liquid chromatography and migration study on HDPE packagings. N. Yagoubi, A. Baillet, C. Mur and D. Baylocq-Ferrier. A quantitative, reversed-phase, liquid chromatography method to quantify trace amounts of phenolic antioxidants is developed. The limits of quantitation of two detectors are compared: one a UV diode-array spectrophotometer and the other electrochemical. The method has also been applied to detect migration phenomena. Five antioxidants were used: propyl-3,4,5-trihydroxybenzoate, 2-tert butyl-4-methoxy phenol, 2-tert butylphenol, 2-tert butyl-4-methylphenol, octyl-3,4,5-trihydroxybenzoate, and one preservative, propyl p-hydroxybenzoate. The linearity range is better with UV, and the detection limit with electrochemical detection. - Chromatographia 35, 455-458 (1993), Centre d'Etudes Pharm., Lab. Chim. Anal., Rue J.B. C16ment, 92290 Chhtenay-Malabry

Spectrophotometric and fluorimetric determination of catecholamines. F.B. Salem. Simple spectrophotometric and spectrofluorometric methods have been described for determination of catecholamines in pharmaceutical formulations using the intensity of the orange colour produced on reaction of catecholamines with the ethanolic solution of ophenylenediamine dihydrochloride at 490 nm and at 560, 410 nm emission maxima with 1,2-diaminoanthracene and 2-aminophenol. The absorbance obeys Beer's law in the concentration range of 0.092 to 2.48 mg of catecholamines spectrophotometrically and from 4.5 to 240 pg spectrofluorometrically. - Anal. Lett. 26, 281-294 (1993). Fac. Pharm., Univ., Mansoura (ET)

(F) Resolution of racemic mixtures of hyoscyamine and colchicine on impregnated silica gel layers. R. Bhushan and I. Ali. The alkaloids (_+)-hyoscyamine and (_+)-colchicine can be separated by TLC on silica gel thin layers impregnated with the optically active acid, L-aspartic acid (0.3%), as the chiral selector. The solvent system n-butanol/chloroform/acetic acid/water (3:6:4:1, v/v), was found to resolve (_+) mixtures. - Chromatographia 35, 679-680 (1993). Dept. Chem., Univ., Roorkee 247667 (IND) Catalytic kinetic determination of trace amounts of ascorbic acid with single-sweep osciUopolarography. Zhi-Liang Jiang and Ai-Hui Liang. The enhancing effect of vitamin C to the V(V)-catalysed reaction of BrO3- and methyl orange in sulphuric acid at 60°C is used for the sensitive, selective and rapid catalytic determination of ascorbic acid using single-sweep d.c. oscillopolarographic detection. The oxidation product of methyl orange exhibits a polarographic wave at 0.40 V vs, SCE in the supporting electrolyte of sodium hydroxide, and was chosen as the indicator component for the indicator reaction. A calibration graph between 8 and 160 ng m1-1 ascorbic acid was obtained by the fixed-time procedure. The detection limit was 4 ng ml - 1. Possible interferences by co-existing substances were examined. Anal. Chim. Acta 278, 5 3 - 5 8 (1993). Lab. Instrum. Anal. Dept. Chem., Guangxi Normal Univ., Guilin (RC) Determination of a biguanide, metformin, by high-performance liquid chromatography with preeolumn fluorescence derivatization. M. Ohta, M. Iwasaki, M. Kai and Y. Ohkura. The hypoglycemic drug metformin can be determined after derivatiza~ tion with the new fluorogenic reagent, desyI chloride, a benzoin analogue, by HPLC on a TSK gel ODS column with a linear gradient of acetonitrile/0.5 Tris-HCl-buffer (pH 8)/water (60:10:30) and acetonitrile/tetrahydrofuran/Tris-HCl-buffer/water(65 : 10:10:15). Phenylguanidine is used as an internal standard. The applicability of the method to the determination of metformin in human serum is demonstrated. The calibration curve of metformin was linear over the range of 0 100 nmol ml-1 in human serum. The detection limit (S/N = 3) was 1.3 pmol per 20-gI injection volume. - Anal. Sci. 9, 217-220 (1993). Daiichi Coll. Pharm. Sci., Tamagawa, Minami, Fukuoka 815 (J) Solid-phase fluoroimmunoassay of insulin using two insulins labeled with a fluorescent sulfobenzoxadiazolyl group. M. Nanami, K. Zaitsu and Y. Ohkura. A labeled position of the fluorescent moiety on the insulin molecule affects the immunoreactivity of the labeled insulin. A solid-phase fluoroimmunoassay of insulin is described, which uses GIy(A1)- and Lys(B29)-[S(4-sulfobenzoxadiazoI-7-yl)-thioglycolyl]-insulins having a fluorescent sulfobenzoxadiazolyl group at a definite position, respectively. The immunoreactivities of these labeled insulins with a mouse anti-porcine insulin monoclonal antibody coated on polyacrylamide beads were compared using porcine insulin. The former labeled insulin provides 1.6-times greater immunoreactivity than does the latter and, thus, can afford a higher sensitivity in the assay. - Anal. Sci. 9, 2 1 3 -

Determination of piroxicam in pharmaceutical preparations by ultraviolet direct spectrophotometriy, ultraviolet difference spectrophotometry and high-performance liquid chromatography. E.R.M. Hackmann, E.A. dos Santos Gianotto and M.I. Rocha Miritello Santoro. Piroxicam in pharmaceutical preparations was determined by UVS at 333 nm, by UV difference spectrophotometry at 327 nm, and by HPLC. For UVS, Beer's law was obeyed in the range 3.0-8.5 gg/ml. The coefficient of correlation, absolute precision and relative precision were 0.9999, 0.02 and 0.33%, respectively. The recovery average (RA) was 100.22%. For UVDS, Beer's law was obeyed in the range 5.0-15.0 gg/ml. In HPLC determination, a LiChrospher 100 RP-18 (5 gin) in LiChroCART 125-4 column with methanol/citric acid-phosphate buffer (pH 3.0) (55:45) as mobile phase and UV detection at 254 nm was used. Linear response was obtained from 10.0 to 100.0 gg/ml. - Anal. Lett. 26, 259-269 (1993). Dept. Farm., Fac. Cienc. Farm., Univ., CEP 05389, S~o Paulo (BR) Fast-responding, fibre-optic based sensing system for the volatile anaestetic halothane, using an ultraviolet absorption technique and a fluorescent film. J.A. Barnard Howie and P. Hawkins. The volatile anaesthetic halothane (2-bromo-2-iodo-l,l,l-trifiuoroethane) can be determined using an UV absorption technique at 230 mn using a silica optical fibre and a fluorescent polymer film. An efficient fluorescent polymer film for the sensor based on poly(ethylene glycol) containing two fluorophores (2,5-diphenyloxazole and tris[4,4,4trifluoro-l-(2-thienyl)butane-l,3-diono]europium(III)) can be used in the excitation range from about 200 to 380 nm. The fluorescent radiaton can be transmitted back to a silicon photo-detector using an inexpensive polymer optical fibre bundle. Two experimental sensor systems for halothane are described and the results show that a reliable system for determining halothane can be constructed, which operates over the medically important range 0 - 3 % . The sensing system could also be used with other gases or liquids that adsorb in the range 200 - 380 nm. Analyst 118, 3 5 - 4 0 (1993). Sensor Res. Group, Fac. Appl. Sci., Univ. West of England, Bristol, GB BS16 105( Determination of monensins A and B in the fermentation broth of Streptomyces cinnamonensisby high-performance liquid chromatography. M. Beran and J. Zima. HPLC on an octadecyl silica column with methanol/water (88:12) as mobile phase has been used to determine both the monensin A: monensin B ratio and the concentration of both in the fermentation broth of Streptomyces cinnamonensis. Refractive index detection was preferred. The coefficients of variation for the estimation both of the ratio and the concentrations of the compounds were better then 5%. The estimated limit of detection for both substances was about 1 gg/mI. Chromatographia 35, 2 0 6 - 208 (1993). Inst. Microbiol. Czechosl. Acad. Sci., Prag 4 (Czech Rep.) HPLC determination of 18 fl-glyeyrrhetinic and glycyrrhizinic acids in toothpastes after solid phase extraction. V. Andrisano, V. Cavrini and D. Bonazzi. HPLC methods suitable for the selective and sensitive determination of 18 [3-glycyrrhetinic acid (GT) and glycyrrhizinic acid (GZ) in toothpastes

216 have been developed. SPE on C- 18 cartridges were used for sample cleanup and concentration. Chromatographic separations were performed on reversed phase (C-8; C-18) columns using mixtures of methanol and phosphate buffers (pH 3.0) as the mobile phase under isocratic or gradient elution conditions. The method were applied successfully to the analysis of commercial toothpastes containing low levels (0.0130.065%) of GT and GZ. A diode array detector was used for identification. - Chromatographia 35, 167-172 (1993). Dept. Pharm. Sci., Univ., 1-40126 Bologna

Determination of phenothiazine drugs and their analogues based on color reaction with Chromazurol B-beryllium(II) complex. Y. Fujita, I. Mori, M. Toyoda and K. Taguchi. A spectrophotometric method for the determination of phenothiazine drugs and analogues (thioxanthene and tricyclic drugs) was established by using Chromazurol B(CAB)-beryllium(II) complex. 1.0 ml of 0.35% sodium N-lauroylsarcosine solution, 0.4 ml of 1.0 x 10 1 M EDTA solution, 3.0 ml of Walpole acetate buffer (pH 4.5) solution, 0.5 ml of 1.0 x 10 -3 M beryllium(II) solution, 1.5 ml of 3.34 x 10 .4 M CAB methanol solution and a solution containing up to about 1.5 x 10 .5 M of each drug was diluted to 10 ml with water and kept at room temperature for 15 min. The absorbance of the resultant solution was measured at 620 nm against reagent blank. The apparent molar absorptivities were (5 ~ 11) x 1041 mol- 1 cm- 1 with the relative standard deviations (n = 8) of (0.6 ~ 1.3)%. The proposed method was applied to the assay of drugs in pharmaceutical preparations. - Bunseki Kagaku 42, T1 - T5 (1993); (Orig. Jap.) Osaka Univ. Pharm. Sci., Matsubara-shi, Osaka 580 (J) Kinetic fluorimetric method for the determination of tobramycin by stopped-flow mixing methodology. A. Gaikwad, A. G6mez-Hens and D. P6rez-Bendito. To determine tobramycin in pharmaceutical products in only 3 - 5 s the reaction with o-phthaldialdehyde in the presence of 2-mercaptoethanol at 335/450 nm was used by stopped-flow mixing methodology. The linear range (0.05 30.0 lag ml 1), detection limit (0.03 Ixg ml-1), precision (%RSD 1.92) and selectivity of the proposed kinetic method are quite acceptable. The method was satisfactorily applied to the analysis of pharmaceutical preparations with no pretreatment. Recoveries of 98.6%. - Anal. Lett. 26, 97--107 (1993). Dept. Anal. Chem., Fac. Sci., Univ., E-14004 C6rdoba Column liquid chromatography of cefadroxil on poly(styrene-divinylbenzene). C. Hendrix, C. Wij sen, Li Ming Yun, E. Roets and J. Hoogmartens. For purity control and assay of bulk samples and of preparations of cefradoxil an isocratic HPLC method on a poly(styrene-divinylbenzene) stationary phase (PLRP-S, 25 c m x 0.46 cm I.D.) at 50°C is proposed. The mobile phase was acetonitrile-0.02 M sodium 1-octanesulphonate0.2 M phosphonic acid-water (10.5:20:5 up to 100, v/v). The flow-rate was 1.0 ml/min and UV detection was performed at 254 nm. Official standards were compared and a number of commercial bulk samples and specialities were analysed. - J. Chromatogr. 628, 4 9 - 5 8 (1993). Lab. Farm. Chem., Inst. Farm. Wetenschappen, Kath. Univ., B-3000 Leuven Resolution of the non-specific spectra of barbiturates by UV-photodiode array detection. II. Effects of sample concentration on spectral matching accuracy. T.W. Ryan. The UV photodiode array detector system allows the accurate and reliable discrimination among the non-specific spectra of five barbiturates at concentrations down to 1 lag/ml. - J. Liquid Chromatogr. 16, 3 3 - 4 9 (1993). Ganes Chemicals Inc., Pennsville, NJ 08070 (USA) Chiral separation of lorazepam on ovomucoid-bonded columns: Peak coalescence due to racemization. H. Fujima, H. Wada, T. Miwa and J. Haginaka. Due to the quick racemisation of lorazepam separations of the enantiomers should be carried out on ovomucoid columns using 20 mM KH2PO4 (pH 6.4)/2-propanol (100:10) as mobile phase. - J. Liquid Chromatogr. 16, 879-891 (1993). Shinwa Chem. Ind., Ltd., Fushimiku, Kyoto 612 (J)

3

Biochemical and clinical analysis

Liquid chromatographic separation of the enantiomers of diniconazole using a fl-cyclodextrin-bonded column. R. Furuta and H. Nakazawa. Enantiomers of the fungicide diniconazole were separated by reversedphase HPLC on a commercially available ~-cyclodextrin (13-CD)-bonded column. The effects of organic modifier in the mobile phase, mobile phase pH and column temperature on the retention and resolution of the enantiomers were studied and optimum conditions were established. Good separation results were obtained on a Cyclobond I column with acetonitrile/water (20: 80). The retention behaviour is discussed. Optical separation of diniconazole using ~-CD as a mobile phase modifier on an octadecylsilanized silica gel column was also investigated for comparison with separation by the above method. - J. Chromatogr. 625, 2 3 1 235 (1992). Environ. Health Sci. Lab., Sumitomo Chemical Co. Ltd., Konohana-ku, Osaka 554 (J) Determination of Suttocide A in cosmetic formulations by single column ion chromatography with pulsed amperometric detection. R.M. Ianiello. To determine the newly developed antimicrobial preservative Suttocide A i n cosmetic products single column anion chromatography is used. After quantitative decomposition of the analyte, the resulting sodium glycinate is separated on a polymeric anion exchange column, using a mobile phase of0.15 M NaOH. Specific detection is accomplished using integrated amperometry at a gold electrode. Inorgnic anions as well as other formulation ingredients do not interfere under the analytical conditions, allowing for a detection limit of 50 ppm Suttocide A in the samples. - J. Liquid Chromatogr. 15, 3045-3063 (1992). Intern. Specialty Prod., Anal. Dept., Wayne, NJ 07470 (USA) Gas chromatographic determination of pesticide residues in hair colours. M. Cetinkaya. A GC-method for the determination of pesticide residues in hair colours is described. The organochloro- and organophosphorus compounds are extracted with acetone/hexane (1:1) and then cleaned by an exclusion chromatographic step. The separation is carried out on a silica gel column with cyclohexane. The quantification can be obtained by GC/ECD or NP-FID on a fused silica OV-1701 capillary column or a DB-I capillary with a temperature program from 175-250°C. The detection limit for organochlorine pesticides is 0.005 mg/kg, for organophosphorus pesticides 0.01 mg/kg and for pyrethroids 0.025 mg/kg. DHCH-isomeres, hexachlorobenzol, dieldrin, endrine, endosulfane and total-DDT could be detected in selected hair colours. - Parfiimerie und Kosmetik 74, 2 3 - 2 5 (1993). Lab. Rfickstandsanalytik Bremen GmbH, Bremen (D)

3

BIOCHEMICAL AND CLINICAL ANALYSIS

International Symposium on Hormone and Veterinary Drug Residue Analysis. Ghent (Belgium), May 19-22, 1992. The topics of this conference lied in the different areas of residue analysis in food and doping analysis. The problems encounterd with residue and doping analysis are very urgent due to the disappearance of borders in the European Community. The Proceedings of the Conference have now been published in Analytical Chimica Acta. The determination of a great variety of drugs such as anabolic steroids, [3-agonists and sulphonamides have been reported. As screening method immunoassays are mainly useful whereas chromatographic and spectroscopic analysis are used as reference methods to confirm the preliminary results. Metabolic studies and determination of illegal administration of other substances like steroid hormones and antibiotics are covered as well. Anal. Chim. Acta 275, 3--358 (1993). Analysis of biological standard reference materials with the SpectroflameICP. G. Stettes and J. Luck. Different NIST-samples for milk powder, wheat and rice flour, orchard and citrus leaves, and pine needles are analyzed by ICP for A1,

3

Biochemical and clinical analysis

As, Pb, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, P, S, Ti and Zn. After pressure-dissolution of the samples with HNO3 in a PDS-6 the analysis is carried out with the Spectroflame-ICP (model P). This apparatus is equipped with a normal combination of ring slit and a Scott-spray chamber. Additionally in some cases an ultrasound nebulizer is valuable. Both sampling systems are compared, conditions for their successfull use are given. In general a good accordance with the certified values is obtained. - Alimenta 32, 8 - 1 0 (1993). Hahn-Meitner-Inst. Berlin, Glienicker Str., W-1000 Berlin 39 (D) The use of displacement chromatography to alter retention and enantioselectivity on a human serum albumin-based HPLC chiral stationary phase: A mini-review. T.A.G. Noctor and I.W. Wainer. A review with 28 references is given about the possibilities to manipulate the chromatographic properties of protein-based HPLC chiral stationary phases (CSPs) using a variety of neutral and charged mobile phase modifiers, like alkyl alcohols and amines, acetonitrile and octanoic acid. Another approach to the control of chromatographic retention (k') and enantioselectivity (~) on a human serum albumin based-CSP, HSA-CSP is to utilize the binding characteristics of the protein. The addition to the mobile phase of warfarin, ibuprofen and tryptophan altered k' and ~ for a variety of solutes. These interactions, their chromatographic applications and pharmacological implications are examined in this presentation. J. Liquid Chromatogr. 16, 783-800 (1993). Dept. Oncol., McGill Univ., Montreal, Quebec, H3G 1Y6 (CDN) Quantitative HPTLC in toxicology. H. Schlitz and F. Erdmann. An overview over the possibilities of the application of HPTLC in toxicological analysis is given which is mainly based on the development of modern TLC-seanner equipment. The quantitative determination of opiates (esp. 6-monoacetylmorphine as heroin marker), 1,4-benzodiazepines via aminobenzophenones, phenothiazines, doping agents, barbiturate derivatives and pesticides by HPTLC is described. - GIT Fachz. Lab. 38, 1 8 - 2 7 0993). Inst. Rechtsmed., Univ., W-6300 Giel3en (D) Bioanalytical application of multidimensional open tubular column supercritical fluid chromatography. L.Q. Xie, K.E. Markides, M.L. Lee, N.K. Hollenberg, G.H. Williams and S.W. Graves. Flow-switching as well as valve-switching interfaces between multidimensional SFC units have been evaluated with special regard to bioanalytical problems. These include the analysis of cholesterol in dried egg yolk, retinoic acids in rat serum, and a digitalis-like factor in peritoneal dialysate from hypertensive patients. A solvent vent injection technique was incorporated in the system, allowing single or multiple volumes of extract (up to 2.0 pl each) to be injected into an uncoated, deactivated, length of capillary precolumn without flooding of the analytical column. For flow-switching, a well-deactivated, glass-lined offsetcross with a small dead volume was placed between the primary and the secondary column. With a rotary valve-switching interface, a cold trap was employed for refocusing analytes at low pressure from single or multiple fractional cuts after being transferred to be second dimension. - Chromatographia 35, 363-371 (1993). Dept. Chem., Brigham Young Univ., Provo, UT 84602 (USA) A new preparation method of calibration graphs for direct analysis of powdered biological samples by solid sampling atomic absorption spectrometry. Standard addition method for solid sampling technique. I. Atsuya, H. Minami and Q. Zhang. A method for the preparation of calibration graphs has been one of the most important problems in solid sampling technique with AAS. The standard addition method for solid sampling technique is proposed for the direct determination of nickel, cobalt, copper and manganese at the ppm levels in powdered biological samples by AAS. Accurate analytical results have been obtained by using a miniature cup with solid sampling. This method is applied to those at the sub-ppm levels in some powdered biological samples, which should be concentrated by a preashing method. For these pre-ashed powdered samples it was also difficult to prepare the calibration graphs. However it becomes possible to obtain good analytical results when the calibration graphs are prepared by the proposed standard addition method for solid sampling tech-

217 nique. - Bunseki Kagaku 42, 167 - 172 (1993); (Orig. Jap.) Kitami Inst. Technol., Hokkaido 090 (J) Estimation of the lower limit of quantitation (LLQ), a method detection performance parameter for biomedical assays, from calibration curves. N. Kucharczyk. A model for the lower limit of quantitation for biomedical chromatographic assays is proposed. It is based on the IUPAC definition for the limit of detection and can be estimated from assay calibration data. It has been applied to ten different sets of calibration data from various assays of drugs in biological matrices. Only the estimation of the LLQ in the simplest and most frequently used case of unweighed least-square fitting is described. - J. Chromatogr. 612, 71 - 7 6 (1993). Wallace Lab. Div., Carter-Wallace, Inc., Cranbury, NJ 08512 (USA) Enantiomeric separation by micellar electrokinetic chromatography using saponins. Y. Ishihama and S. Terabe. The triterpene glucosides, glycyrrhizic acid (GRA) and [~-escin, were employed in micellar electrokinetic chromatography for enantiomeric separation. Both GRA and 13-escin are saponins and natural chiral surfactants. A mixed micelle consisting of 30 mM GRA, 50 mM octyl~-D-glucoside and 10 mM borate-10 mM phospate buffer (pH 7) was successfully used for enantiomeric separation of dansylated DL-amino acids. [3-Escin was also employed to prepare a mixed micelle with SDS and the mixed micelle was capable of separating phenylthiohydantoinDL-amino acids under acidic conditions (pH 3). - J. Liquid Chromatogr. 16, 933 - 9 4 4 (1993). Dept. Ind. Chem., Fac. Engin., Univ., Kyoto 606 (J) Biosensor calibration. In situ recalibration of competitive binding sensors. S.G. Weber and A. Weber. An approach for biosensor calibration is proposed where 8 sensors are used to monitor changes in the three parameters and a ninth sensor provides the signal This signal is modified according to changes in the parameters; the process is termed recalibration. This theoretical work shows how to recalibrate sensors that are based on the principles of competitive binding. Simulations show the usefulness and limitations of the procedure. - Anal. Chem. 65, 223 - 2 3 0 (1993). Dept. Chem., Univ. Pittsburgh, Pittsburgh, PA 15260 (USA) Sensitive 'one drop' flame atomic absorptiometric determination of cadmium in botanical samples using direct nebulization of chloroform extract. I. Kojima and S. Kondo. A combined technique for the preconcentration of trace amounts of Cd and the determination by sensitive 'one drop' flame AAS for the sensitive determination of Cd in biological samples is developed. After microwave digestion of solid samples with an acid mixture and the removal of iron in the sample solution by extraction with 2-hydroxy-4isopropylcycloheptatrienone dissolved in benzene, the cadmium-ammonium pyrrolidin-l-yldithioformate (APDC) complex was extracted into chloroform. Direct nebulization of the chloroform extract of cadmium-APDC complex into the flame gave a very sensitive signal intensity. The detection limit obtained with an injection volume of 40 gl was 1.2 ng ml-1 or 50 pg [signal-to-noise ratio (S/N) = 3]. Cadmium was determined by 'one-drop' flame AAS with deuterium background correction with an injection volume of 40 gl of chloroform extract. The present method was successfully applied to the determination of cadmium in botanical certified reference materials. - J. Anal. At. Spectrum. 8, 115-118 (1993). Lab. Anal. Chem., Dept. Appl. Chem., Inst. Technol., Nagoya 466 (J) The hydrogen ion dependence of amperometric detection of a202 and hexacyanoferrate ions and the pH profiles of immobilized enzyme preparations. J.J. Baeza Baeza, K. Matsumoto and H.A. Mottola. Enzyme-catalyzed reactions (e.g. those involving oxidases) produce H202 as a product. The Fe(CN)63-/Fe(CN)64- redox couple is frequently used as an indicator reaction to follow enzyme-catalyzed reactions. If the detection approach is electrochemical, the pH dependence of the half-redox reaction affects the overall pH dependence of the initial rate response recorded in such cases. Rotating enzyme reactors conveniently permit study of the optimum pH at which a given

218 immobilized enzyme preparation can catalyze the reaction involving a given substrate. Selecting model enzyme-catalyzed systems (employing glucose oxidase, EC 1.1.3.4; alcohol oxidase, EC 1.1.3.13; sulfite oxidase, EC 1.8.3.1 ; and D- fructose 5-dehydr0genase, EC 1.1.99.11) the capabilities of rotating reactors in studies ofpH profiles are illustrated. Particular attention is given to correction for the indicador reaction dependence on pH and the dependence of overall performance on buffer capacity. Quim. Anal. 12, 12 17 (1993). Dept. Chem., Oklahoma State Univ., Stillwater, OK 74078-0447 (USA)

Enzymatic determination of carbon-14-1abeled D-/i-hydroxybutyrate in biological samples. S. Quevedo, A. Palou and P. Roca. A method for D-~-hydroxybutyrate-specific radioactivity determination is proposed which is based on the highly specific enzymatic transformation of D-[3-hydroxybutyrate to acetoacetate catalyzed by the enzyme 13-D-hydroxybutyrate dehydrogenase, coupled to the simultaneous formation of the respective phenylhydrazone derivative. This phenylhydrazone can be quantitatively trapped in a simple step by SPE ehited with ethanol and measured by radioactivity counting. By comparison with the enzymatically untreated samples the radioactivity can be estimated. No interferences from other 14C-labeled materials such as D-glucose, L-alanine, L-glutamine, and L-valine were observed. This inexpensive and high-speed method can be applied in routine multiple estimations of D-13-hydroxybutyrate-specific radioactivity in biological samples in tracer metabolic studies. - Anal. Chem. 65, 992-993 (1993). Dept. Biol. Fon. Clan. Salut, Univ. Illes Balears, Inst. d'Est. Avan. (UIBCSIC), Ctra Valldemossa Km 7.5, E-07071 Palma de Mallorca (E) Detection of carbohydrates by capillary electrophoresis with pulsed amperometric detection (PAD). T.J. O'Shea, S.M. Lunte and W.R. La Course. The feasibility of PAD as a detection method for capillary electrophoresis is explored. PAD is used at a microelectrode in a flowing stream. A system has been developed using off-column detection and a gold wire microelectrode. The separation and detection by CE-PAD of several charged carbohydrates of biological interest are presented. The use of this detector for the determination of glucose in blood is demonstrated. - Anal. Chem. 65, 948-951 (1993). Center Bioanal. Res., Univ., Kansas, Lawrence, KS 66047 (USA) Design of a glucose minisensor based on streptavidin-glucose oxidase complex coupling with self-assembled biotinylated phospholipid membrane on solid support. M. Snejdfirkovfi, M. Rehfik and M. Otto. The construction of a glucose-sensitive mini-biosensor based on biotinylated phospholipid and streptavidin-modifiedglucose oxidase conjugate is described. The assay isbased on the electrochemical detection of enzymatically generated hydrogen peroxide at the potential + 670 inV. In an air-saturated buffering solution the response to glucose was measured up to 50 mmol-1-1, with a linear portion up to 7 retool.l- 1. The influence of oxygen tension, pH, and temperature as well as possibility interfering substances was investigated. The prospect usage for the measurement of diluted blood and urine was tested. - Anal. Chem. 65, 6 6 5 - 668 (1993). Inst. Animal Biochem. Gen., Slovak Acad. Sci., 90028 Ivanka pri Dun@ (Slovakia) Selective detection of chlorine-containing compounds by gas chromatography]chemical reaction interface mass spectrometry (CRIMS). H. Song and F.P. Abramson. CRIMS with SO2, but not HBr, combines high sensitivity, high selectivity, a wide linear range and structure independence for chlorine detection in GC. With SO2, a detection limit of 50 pg of diazepam and a linear range of 4 orders of magnitude were achieved, and the experimental data were reproducible. With HBr, the detection limit was 10 ng of diazepam and the linear dynamic range was only 2 orders of magnitude. The possible pharmacological application of CRIMS was studied using urine spiked with diazepam and several of its metabolites, and the results show CRIMS to be a simple but potentially powerful method in drug metabolism studies. -- Anal. Chem. 65, 447--450 (1993). Dept. Pharm., George Washington Univ., Washington, DC 20037 (USA)

3

Biochemical and clinical analysis

Simultaneous determination of trace metals in human hair by dynamic ion-exchange chromatography. A. Sturaro, G. Parvoli, L. Doretti, S. Zanchetta, G. Allegri and G. Battiston. The use of LC (in the mode of dynamic ion-exchangechromatography) is reported for the determination of Cu 2+, Zn 2+, Ni 2+, Mn 2+, Co 2+, Pb 2 + in hair after HNO3-HC104 digestion with detection limits of ca. 1 gg g-1 for all the metals examined, using Co as an internal standard. The quantitative data were confirmed by analysing the same hair samples by atomic absorption spectrometry and x-ray fluorescence spectrometry. - Anal. Chim. Acta 274, 163-170 (1993). Uff. Sicur., Prevenz. CNR, 35020 Padova (I) Metal porphyrin chemiluminescence reaction and application to immunoassay. M. Motsenbocker, Y. Ichimori and K. Kondo. An optimized metal porphyrin chemiluminescence system with tuminol is developed which extremely good sensitivity (68 amol of antibody conjugate). The recommended reaction solution contains 1 mM himinol and 0.1% linoleic acid in 0.1 M NaOH (pH 13). Mn-porphyrine with meso(4) tetra electron withdrawing groups seems to be the best catalyst. An cz-fetoprotein immunoassay developed using the chemiluminescence reaction had a detection limit of 20 pg (0.2 fmol). Because the reaction solution needed for methyl porphyrin chemiluminescence is very simple and has good stability, this chemiluminescence detection system may have application to automated assays. Anal. Chem. 65, 3 9 7 - 402 (i 993). Takeda Chem. Ind., Ltd., Pharm. Div., Yodogawa-ku, Osaka 532 (J) Determination of mercury in urine by flow-injection cold vapour atomic absorption spectrometry. Tiezheng Guo and J. Baasner. Total mercury in urine samples can be determined by on-line addition of KMnO4 after adding a bromate-bromide reagent to the sample to decompose organic mercury compounds to inorganic mercury(II) ions at room temperature, and flow-injection cold vapour atomic absorption spectrometry. The recoveries of five mercury compounds added to urine were studied; good agreement with certificate values of urine reference materials was obtained. The detection limit of the method based on three standard deviations of the blank was 0.1 gg Hg 1-1 in urine with a 500-gl sample loop, achieving a sample throughput of 100 h 1. The calibration graphs were linear up to 30 gg 1-1 and with a dynamic range up to 100 pg Hg i -1. At a concentration of 5 p.g Hg 1-1 in urine, the relative standard deviation was about 2%. - Anal. Chim. Acta 278, 189 - 196 (1993). At. Absorpt. Prod. Dept., Bodenseewerk Perkin-Elmer GmbH, 88662 Uberlingen (D) Affinity biosensors based on preconcentration/voltammetric analysis. Detection of phenothiazine drugs at Langmuir-Blodgett films of tyrosine hydroxylase. J. Wang, Yuehe Lin, A.V. Eremenko, I.N. Kurochkin and M.F. Mineyeva. A new voltammetric approach is described to follow host-guest interaction. The receptor binding process of the affinity biosensor serves as an in situ preconcentration step of the target analyte. The accumulated analyte is being quantified by voltammetry. The receptor layer also serves as an effective barrier that excludes interfering species. The new concept of preconcentration/voltammetric affinity biosensors is illustrated in connection with the detection of phenothiazine drugs using Langmuir-Blodgett films of their receptor, the enzyme tyrosine hydroxylase. The effect of various experimental variables upon the sensor performance is described. - Anal. Chem. 65, 513-516 (1993). Dept. Chem., New Mexico State Univ., Las Cruces, NM 88003 (USA) Amperometric sensors for peroxide, choline and acetylcholine based on electron transfer between horseradish peroxidase and a redox polymer. M.G. Garguilo, Nhan Huynh, A. Proctor and A.C. Michael. Hydrogen peroxide, choline, and acetylcholine can be determined by sensors based on the immobilization of horseradish peroxidase, (HRP), choline oxidase, and acetylcholinesterasein a cross-linked redox polymer deposited on glassy carbon electrodes. The sensors developed uses as many as three consecutive enzymatic reactions to generate amperometric response. With a single sensor two detection schemes can be switched simply by adjusting the electrode potential with respect to the E1/2 of the mediator. Peroxide sensors, prepared by immobilization of HRP

3

Biochemical and clinical analysis

alone, gave detection limits of 10 nM and a linear response up to ca. 1 raM. Coimmobilization of HRP and glucose oxidase was used to establish the feasibility of highly efficient bienzyme sensors at low substrate levels. Replacing glucose oxidase with choline oxidase produced sensors with submicromolar detection limits and a linear response up to 0.8 raM. Addition of acetylcholinesterase to the sensors generated a relatively small response to acetylcholine. - Anal. Chem. 65, 523-528 (1993). Dept. Chem., Univ., Pittsburgh, PA 15260 (USA)

Application of capillary zone electrophoresis to the separation of metallothionein isoforms. M.P. Richards, J.H. Beattie and R. Self. Metallothioneins (MTs) from various eukaryotic species can be characterized by CZE under the following conditions: capillary: untreated polyimide-clad fused silica 75 gm i.D. x 94 cm; loading and running voltage: 30 kV; electrode buffer: 50 mM Tris-HC1 pH 9.1; sample buffer: 10 mM Tris-HCl pH 9.1; sample volume: 250 gi; detection: UV absorbance at 214 nm; loading method: electrokinetic migration; loading times: 1 - 6 seconds. Complete separation of MT-I and MT-2 isoforms was achieved in less than 6 min. With appropriate standardization CZE is capable of both qualitative and quantitative determinations of MT isoforms. In CZE, the concentration of MT in solution determines the limit of sensitivity. MT could be accurately detected at a concentration as low as 10 tag/ml. - J. Liquid Chromatogr. 16, 2113-2128 (1993). The Rowett Res. Inst., Bucksburn, Aberdeen, AB2 9SB (GB) Capillary electrophoresis coupled to fluorescence detection for the determination of in vivo release of multiple neuropeptides from the ewe median eminence (ME). J.P. Advis and N.A. Guzman. A capillary electrophoresis (CE)-based assay for the simultaneous determination of luteinizing hormone-releasing hormone (LHRH), [3endorphine ([3END) and neuropeptide Y (NPY) in push-pull canula samples from the ewe ME is described. This assay uses CE for the separation of these neuropeptides and their derivatization with the fluorogenic chromophore fluorescamine to amplify their signal. The CE-based assay allows the simultaneous electrophoretic assessment of endogenous NPY and [~END. However, simultaneous detection of endogenous LHRH is only marginal. A working assay for LHRH might only be achieved when laser-induced fluorescence detection of derivatized neuropeptides is coupled to additional sensitivity enhancers already in existence. An appealing aspect of this technology is the simplicity of the methodology, its efficiency coupled to the need of low volume samples, and most important, its ability to separate and to detect multiple neuropeptide components, simultaneously, in a single sample. - J. Liquid Chromatogr. 16, 2129-2148 (1993). Dept. Animal Sci., Rutgers Univ., New Brunswick, NJ 08903 (USA)

219 Optimization of separation of porphyrins by miceHar electrokinetic chromatography using the overlapping resolution mapping scheme. Y.J. Yao, H.K. Lee and S.F.Y. Li. The use of a systematic optimization scheme for the separation of nine porphyrine free acids after CE separation has been demonstrated. Three buffer parameter have been included in the overlapping resolution method, viz., surfactant (sodium dodecyl sulphate) concentration, amount of organic modifier (N,N-dimethylformamide) and the ionic strength of the buffer. To utilize the scheme, a set of seven preplanned experiments were performed. Optimum separation conditions were determined which provided satisfactory separation of the porphyrins within an analysis time of ca. 30 min. - J. Chromatogr. 637, 195-200 (i993). Dept. Chem., Nat. Univ., Singapore 0511 (SGP) Qualitative analysis of mycotoxins using micellar electrokinetic capillary chromatography (MECC). R.D. Holland and M.J. Sepaniak. The capabilities of MECC for the separation of naturally occuring mycotoxins are investigated. The infuence of the composition and the pH of the mobile phase was studied. Two sets of mobile phase composed of phosphate/borate buffer with the addition of surfactants like SDS or sodium deoxycholate provide unique selectivity. Two distinctive, fully resolved chromatograms of 10 mycotoxins in ca. 45 rain can be obtained with coefficients of variation less than 1%. The utilization of normalized retention times applied to separation obtained with two sets of mobilephase conditions permitted the identification of all the mycotoxins in five unknown samples without any misidentifications. - Anal. Chem. 65, 1140-1146 (1993). Dept. Chem., Univ. of Tennessee, Knoxville, TN 37996-1600 (USA) Determination of fluoride in complex liquid matrices by electrothermal atomic absorption spectrometry with in-furnace oxygen-assisted ashing. G. Cobo, M. Gomez, C. Camara and M.A. Palacios. A new chemical method is reported for the determination of total fluoride in complex liquids and suspensions, such as fruit juices, urine, serum and blood. It is based on the formation of the A1F radical in a graphite furnace after in situ oxygen-assisted ashing of the untreated sample. The absorbance of this radical is measured at 227.45 nm. The method is relatively easy to use and provides a low detection limit (14 ng/ml) and reasonable reproducibility (5-10%). - Mikrochim. Acta 110, 103--110 (1993). Dept. Anal. Chem., Fac. Chem., Complutense Univ., E-28040 Madrid (E)

Screening and characterization of biopharmaceuticals by high-performance capillary electrophoresis with laser-induced native fluorescence detection. T.T. Lee, S.J. Lillard and E.S. Yeung. HPCE with laser-induced native fluorescence (LIF) detection is used in the quality control of biopharmaceuticaIs. HPCE/LIF can determine impurities in "purified" biopharmaceuticals present in amonts less than 0.01% (i.e., at 4 x 10 11 M) that of the major component. - Electrophoresis 14, 429-438 (1993). Dept. Chem. Ames, Lab.-USDOE, Univ., Ames, IA (USA)

Catalytic determination of molybdenum(VI) in plants using mono-segmented continuous-flow analysis (MCFA) and spectrophotometric detection. J. Carlos de Andrade, R.E. Bruns and S. de Paula Eiras. Mo can be determined in plants by a MCFA procedure which is based on the catalytic oxidation of I by H202 in acid medium as the indicator reaction and spectrophotometric detection at 350 nm. High sensitivity was achieved using multivariate and univariate screening experiments, optimized reagent concentrations, a reaction time of 130 s and a sampiing-loop volume of 300 gl or higher. The reagents were pumped at 1.2 ml min-1 and the sample at 4.7 ml min-1, yielding a sampling rate up to 120 1, with negligible carryover. Interferences caused by Fe(III), W(VI), Cr(VI), V(V) and PO43- can be eliminated by a separation step, where Mo(VI) is extracted. - Analyst 118, 213-217 (1993). Univ. Est. Camp., Inst. Quim., CP 6154, 13081-970, Campinas-SP (BR)

Novel electrochemical device for the detection of cholesterol or glucose. J.F. Cassidy, C. Clinton, W. Breen, R. Foster and E. O'Donoghue. A thin-layer twin-electrode electrochemical cell in which the working and auxiliary electrodes are facing each other and which contains the appropriate enyzme and a mediator was used for the determination of cholesterol or glucose. A steady-state time-independent diffusioncontrolled response was obtained for cholesterol whereas for glucose the response was limited by diffusion and kinetics. Simulation of the system showed that a steady-state response is obtained. Linear plots of steadystate current versus concentration were obtained for cholesterol and glucose. The results were compared with those expected theoretically and a thin-layer capillary fill device is proposed. -- Analyst 118, 4 1 5 418 (1993). Chem. Dept. Dublin Inst. Technol., Dublin 8 (IRL)

A colorimetric assay for amino nitrogen in small volumes of blood: reaction with/~-naphthoquinone sulfonate. P.C. Evans, F.M. Ffolliot-Powell and J.E. Harding. A modified color!metric assay of amino nitrogen in blood (100 pl) has been described. The procedure utilizes the reaction of amino nitrogen with ~-naphthoquinone sulfonate. It represents a substantial improvement on previously published methods by decreasing reagent volumes and accurately specifying and maintaning pH conditions for the reaction itself (9.2-9.4) and for removal of excess reagent prior to measurement of the resulting complex (2.2--2.4). Ammonia is the only compound shown to significantly interfere with the assay but this is not a problem at physiological concentrations. - Anal. Biochem. 208, 334-337 (1993). Res. Cent. Develop. Med., Biol., Univ., Auckland (NZ)

220 High-performance liquid chromatographic determination of methanesulphinic acid as a method for the determination of hydroxyl radicals. S. Fukui, Y. Hauasaki and S. Ogawa. An HPLC method is developed for the determination of hydroxyl radicals based on the reaction of "OH and dimethylsulfoxid. The resulting methanesulphinic acid was reacted with Fast Yellow GC salt and determined by HPLC on a Capcell-Pak NHz column with ethanol/nhexane (3:100) and UV detection at 285 nm. The results for hydroxyl radicals formed using the Fenton and hypoxanthine-xanthine oxidase systems agreed well with the theoretical values. Interferences from phenols, aromatic amines and amino acids, which give coloured substances by reaction with the diazonium salt, could be avoided. The recovery of methanesulphinic acid added to liver homogenates and incubated for l h at 37°C was 70.2 ± 2.1%. The detection limit for methanesulphinic acid in a sample solution was ca. 8 ng/ml. - J. Chromatogr. 630, 1 8 7 193 (1993). Pharrn. Univ., Yamashina-ku, Kyoto 607 (J) Analysis of mercury in the low nanogram range. H. Tasche, M. Otto, T. Griinberg, C. Ahlemeyer and K.E. yon Mithlendahl. A new system for mercury analysis is described which is based on CVAAS which is able to detect Hg in urine below the usual level of 0.5 gg/1. A careful optimization of the sample preparation is necessary to obtain valid results. The use of stannous chloride as reduction agent results in a better detection sensitivity, but requires necessarily a hydrolysis or mineralization step for the analysis of organomercury compounds. With sodium borohydride as reducing agent a 3 to 4 fold worse sensitivity is obtained, however inorganic as well as organic merury can be measured without prior sample destruction. - GIT Fachz. Lab. 37, 411-413 (1993). Dokumentations- und Inform., Stelle Umweltfragen der Kinder/irzte, W-4500 Osnabriick (D) Determination of lead in biological materials by microwave-assisted mineralization and flow injection electrothermal atomic absorption spectrometry. J.L. Burguera and M. Burguera. Design and operation of a time-based on-line automated microwave assisted digestion system followed by introduction of the digest into an FI-ETAAS system is described for the determination of lead in some biological sample. Certified reference materials were homogeneously dispersed in a 0.4% v/v Triton X-100 solution with an ultrasonic device. Mineralization of samples was accomplished with an HC1-HNO3 plug downstream in a PTFE coil located inside the microwave oven. A gas diffusion cell device allowed efficient degasification of mineralized samples. Precise volumes of the mineralized samples were introduced by means of positive displacement with air through a time-based solenoid injector into the graphite furnace. The entire system was controlled by a computer, independent of the spectrometer. The linear range was from 0 to 70 pg 1 1 of lead and the detection limit was 0.1 gg 1-1 (0.8 pg). The agreement between observed and certified values was good. - J. Anal. At. Spectrom. 8, 235-241 (1993). Dept. Chem., Fac. Sci., Univ. Los Andes, M&ida 5101-A (YV) Determination of cadmium in biological materials by tungsten coil atomic absorption spectrometry. M.F. Gin~, F.J. Krug, V.A. Sass, B.F. Reis, J.A. N6brega and H. Berndt. Low cost tungsten coil furnaces are used for the accurate determination of Cd in biological digests by ET-AAS. The open atomizer was resistively heated by using a power supply with a voltage feedback circuit. The analysis time using a manually injected sample volume of 10 gl was 41 s. Acceptable precision (RSD < 3%, n = 12 at 1.0 ng ml- 1 of cadmium) was obtained for cadmium values ranging from 0.5 to 6.0 ng ml-1. The characteristic mass for peak height absorbance was 0.5 pg. Results compare well with certified values of different biological materials digested with nitrid acid. - J. Anal. At. Spectrom. 8, 243-245 (1993). Inst. Spektrochem., Angew. Spektrosk., W-4600 Dortmund (D) Speciation of mercury in fish samples by solvent extraction, methylmercury reduction directly in the organic medium and cold vapour atomic absorption spectrometry (CVAAS). M. do Carmo R. Rezende, R.C. Campos and A.J. Curtius. The possibility of speciation of Hg by selectively extracting the organomercury compounds with chloroform and determining Hg by CVAAS

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Biochemical and clinical analysis

based on direct reduction in the organic solvent is investigated. Parameters studied include the nature and concentration of the reductant and the acid stirring time. No matrix effect was observed. Inorganic Hg was determined in the residual aqueous phase by reduction with NaBH4. Spiking studies showed good recoveries of 102_+2%. The procedure was applied to fish samples. The detection limit (3~) for the total analytical procedure was 25 ng of Hg (as CHaHg +) per gram of wet sample. - J. Anal. At. Spectrom. 8, 247-251 (1993). Dept. Quire., Univ. Estadual de Maringfi, Paran~i (BR) Assessment of metals in reconstituted metallothioneins by electrospray mass spectrometry. X. Yu, M. Wojciechowski and C. Fenselau. Metallothionein complexes with 7 divalent metals which are coordinated by 20 sulthydryl groups can be analyzed by electrospray MS if care is taken to the pH values. The metal-free apoprotein was detected with its most abundant ions in a charge state of 6 + , while the folded metallothionein-metal complexes were observed with lower charge states. This mass spectrometric technique can be used to determine rapidly and accurately how many and what cations are incorporated per molecule of protein. - Anal. Chem. 65, 1355 - 1359 (1993). Dept. Chem. Biochem., Univ. Maryland Baltimore County, Baltimore, MD-21228 (USA) Determination of thiol and disulfide groups on the basis of an argentometric-amperometric method. J. Kroll and R. Kr6ck. Thiol and disulfide groups in proteins can be determined by amperometric titration with silver nitrate. A variable working dosimeter is described to make this method more simple and sensitive. The apparatus is used for the determination of glutathion(Ox) and ovalbumin. Food 37, 7 4 - 7 6 (1993). Deutsch. Inst. Ern~ihrungsforsch., PotsdamRehbrtieke (D) TLC separation of linamarin, linustatin and neolinustatin. R. Amarowiez, P.K.J.P.D. Wansundara and F. Shahidi. The cyanogenic glycosides linamarin, linustatin and neolinustatin can be separated from flaxseed samples by TLC on HPTLC plates. The sample solutions were applied in absolute methanol. The separation of the glycosides from rapeseed can be carried out in chloroform/methanol/ 17% NH4OH, or ethyl acetate/acetone/chloroform/methanol/water (40:30:12:10:8). The glycosides were separated in chloroform/methanol/water (65:35:10), whereas for the separation of the oligosaccharides n-propanol/water (85:15), n-butanol/acetone/water (75:75:25) and ethyl acetate/acetic acid/methanol/water (60:15:15:10) is a useful mobile phase. Spots were visualized by spraying with 10% H2SO4 and heating at 120°C for 10 min. - Food 37, 88 - 9 1 (1993). Dept. Biochem., Univ. Newfoundland, St. John's (CDN) Separation characteristics of polyethylene glycol coated capillary for capillary electrophoresis (CE). M. Mizuno, K. Tochigi and M. Taki. Capillaries for CE were modified with polyethylene glycol (PEG), following cross-linking with dicumyl peroxide (DCP), in order to reduce the interaction of proteins with fused-silica capillary surfaces and obtain good separation. Coating thickness and concentration of DCP were 25 nm and 10%, respectively. Effects of pH and concentration of the buffer solutions were studied. PEG coated capillary showed best resolution at pH 3.5-5.0. 7 x l0 s plate.m -1 could be obtained for cytochrome c with 50 mM potassium phosphate at pH 3.8, 2.8 times larger than on uncoated capillaries. PEG coated capillary showed a significant decrease in the protein adsorption in comparison to uncoated capillaries. -Bunseki Kagaku 42, 7 - 1 2 (1993); (Orig. Jap.) Hitachi Res. Lab., Hitachi Ltd., 7-7-1, Omika-cho, Hitachi-shi, Ibaraki 319-12 (J) Electrochemical detection of dipeptides with selectivity against amino acids. S.G. Weber, Hweiyau Tsai and M. Sandberg. It is possible to detect dipeptides with some selectivity at a modest potential in weakly alkaline solutions. Electrolysis of a basic mobile phase containing biuret reagent [Cu(II) and a tartrate salt] at high ( > 1.2 V vs. Ag/AgC1) potentials modifies the glassy carbon electrode. This modified anode oxidizes dipeptides, yielding signals expected for a oneelectron transfer, even at low (down to 0.7 V vs. Ag/AgC1) potentials and in the absence of intentionally added copper(II) ion in the reagent

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Biochemical and clinical analysis

or mobile phase. The same modification demonstrates a selectivity to ~zdipeptides over amino acids that is unprecedended. Sensitivities for several amino acids and dipeptides are reported under several conditions. - J. Chrornatogr. 638, 1 - 8 (1993). Dept. Chem., Univ., Pittsburgh, PA 15260 (USA)

Trace analysis of proteins by capillary zone electrophoresis with on-column transient isotachophoretic preconcentration. F. Foret, E. Sz6ko and B.L. Karger. Transient isotachophoretic sample preconcentration can be used for in the capillary zone electrophoretic analysis of protein samples. Two basic electrolyte arrangements have been employed. In the first, a typical isotachophoretic electrolyte system consisting of a leading and terminating electrolyte was used, and after focusing and preconcentration, the terminating electrolyte was replaced by the leading electrolyte, with the separation being continued in the zone electrophoretic mode. In the second, only one background electrolyte was used, containing a co-ion with low electrophoretic mobility, and the sample was supplemented with a salt of a highly mobile co-ion. In this case transient isotachophoretic migration of the sample ion took place at the beginning of the migration and gradually changed to the zone electrophoretic mode. The isotachophoretic sample stacking permitted injection and preconcentration of sample volumes two to three orders of magnitude higher than usual in capillary zone electrophoresis. - Electrophoresis 14, 417-428 (1993). Northeastern Univ., Barnett Inst., Boston, MA (USA) Use of small-diameter capillaries for increasing peptide and protein detection sensitivity in capillary electrophoresis-mass spectrometry. J.H. Wahl, D.R. Goodlett, H.R. Udseth and R.D. Smith. Small ID capillaries provide an increase in sensitivity for capillary electrophoresis-electrospray ionization/mass spectrometry. Using capillaries ranging from either 100 to 10 pm or 50 to 5 lam ID and chemically modified with aminopropylsilane, a 25- to 50-fold increase in sensitivity was observed for both peptide and protein mixtures. This enhanced solute sensitivity allowed the detection of approximately 150 attomoles of melittin (2845 Da) with selected ion monitoring and 600 attomoles of carbonic anhydrase (29157 Da) while scanning for CE-MS with a quadrupole mass spectrometer. This increase can be primarily attributed to a reduced mass flow rate of buffer and other background constituents into the electrospray source. A model that qualitatively accounts for the results is presented. The results suggest peptide and protein analysis at low attomole and subattomole levels should be obtainable with alternative types of mass spectrometers. - Electrophoresis 14, 448 - 4 5 7 (1993). Chem. Methods, Sep. Group, Chem. Sci. Dept., Pacific Northwest Lab., Richland, WA (USA) Fast analysis of proteins by isoelectric focusing performed in capillary array detected with concentration gradient imaging system. Jiaqi Wu and J. Pawliszyn. By the combination of universal concentration gradient detector, imaging system and capillary isoelectric focusing (CIEF) protein separated simultaneously in an array of 2 4 short capillaries can be detected in 2 - 3 rain, which is about 100 time faster than the conventional gel slap isoelectric focusing and 10 times faster compared to conventional CIEF. The resolution of the separation is 0.02 pH units or better. The concentration limit of detection for this inexpensive instrument is about 30 pg/ml and can be reduced by using higher quality components in the system. The sample consumption is 400 nl for the 4 cm long, 100 gm ID square capillary. - Electrophoresis 14, 469-474 (1993). Dept. Chem., Univ., Waterloo, Ontario (CDN) High-performance capillary electrophoresis of glyeoeonjugates. M.V. Novotny and J. Sudor. Taking into account 76 references a review is given about the utility of capillary electrophoresis (CE) as a highly promising technique for the analysis and structural study of glycoconjugates. The separation media suitable for the analysis of monosaccharides, oligosaccharides and very large carboyhydrate-based biomolecules are discussed. The detection aspects emphasize chemical derivatization approaches to tagging the glycoconjugates of interest for enhanced response in absorption and

221 fluorescence spectroscopy. - Electrophoresis 14, 373 - 389 (1993). Dept. Chem., Univ., Bloomington, IN (USA)

Determination and derivatization of protein thiols by n-octyldithionitrobenzoic acid (ODNB). H. Faulstich, P. Tews and D. Heintz. ODNB can be used for the fast titration of SH groups in proteins. Normally, endpoints are reached after 5 - 30 rain, while the corresponding reaction with Ellman's reagent may take l - 2 h. The n-octylthiol derivatives of proteins formed by reaction with ODNB can be used for transient protection of thiols, for example, during purification procedures, or for a reversible blocking of SH groups involved in biochemical reactions. - Anal. Biochem. 208, 357 - 362 (1993). Max Planck Inst. Med. Forsch., W-6900 Heidelberg (D) An assay to detect glycoproteins that contain mannose 6-phosphate. K.J. Valenzano, L.M. Kallay and P. Lobel. A solid phase assay for quantitative and qualitative analysis of phosphorylated lysosomal enzymes and other glycoproteins that contain mannose 6-phosphate (Man6-P) residues is described. Samples are immobilized on membranes and proteins that contain Man6-P are detected using an iodinated, soluble form of the cation-independent Man6P receptor. The assay is highly specific, sensitive, and linear over 3 orders of magnitude. The technique can be used in a dot blot format to analyze large numbers of samples for total levels of Man6-P glycoproteins, and in a western blot format to identify Man6-P glycoproteins that have been fractionated by polyacrylamide gel electrophoresis. - Anal. Biochem. 209, 156--162 (1993). Cent. Adv. Biotechnol. Med., Dept. Pharmacol., Univ. Med., Dent., Piscataway, NU 08854 (USA) Optimization of capillary electrophoresis of mixtures of basic peptides and comparison with HPLC. H.-J. Gaus, A.G. Beck-Sickinger and E. Bayer. Capillary electrophoresis can be used especially in the micellar electrokinetic mode as efficient tool for the separation of peptides with different charges and peptides with different charge orientation due to different secondary structure. Fourteen synthetic, strongly basic hexadeca- to octadecapeptides, which differ only in one amino acid residue, were analyzed by HPLC and different techniques of capillary electrophoresis. Peaks within the mixture were identified by singe peak injection or on-line CE/MS. - Anal. Chem. 65, 1399-1405 (1993). Inst. Org. Chem., Univ. Tfibingen, W-7400 Tiibingen (D) Ion-pair LC of sugars at alkaline pH and pulsed electrochemical detection. M. Stefansson and B. Lu. At pH _> 11 sugars, sugar acids, amino sugars and oligomers are separated as ion-pairs with hydrophobic counter ions at alkaline pH using PLRP-S and Hypercarb as solid phases. Important parameters for regulation of retention and selectivity are nature and concentration of the counter ion, pH (hydroxide concentration) and temperature. Oligosaccharides are highly retained in these systems. Organic modifiers were found to interfere with the pulsed electrochemical detection. Anions added to the mobile phase compete with the solutes for ion-pair retention, hence, decreasing the capacity factors. - Chromatographia 35, 6 1 - 6 6 (1993). Anal. Pharm. Chem., Univ. Biomed Cent., 75123 Uppsala (S) Separation of sugars by ion-exclusion chromatography on a cation-exchange resin. L. Rodin, M. Rod6n, Hao Yu, Jin Jin and J. Greenshields. N-acetylmannosamine and N-acetylglucosamine can be separated by chromatography on a column (30 x 1 cm) with the cation-exchange resin, Dowex 50W-X2, in borate buffer at pH 7.8. N-acetylmannosamine is eluted near the void volume, while N-acetylglucosamine emerges in a more retarded position. The separation occurs as a result of the combined effects of ion exclusion and gel permeation. In borate solution, Nacetylmannosamine presumably exists largely as a negatively charged complex and is therefore excluded from the sulfonated polystyrene matrix, while N-acetylglusosamine occurs mainly as the free sugar in the equilibrium mixture and, being a neutral compound, has free access to the porous resin. The proposed mechanism for the separation was supported by the finding that glucose and glucose 6-phosphate could also be separated on a column of the same resin, with water as the

222 eluent. - J. Chromatogr. 638, 2 9 - 3 4 (1993). Univ., Birmingham, AL 35294 (USA) Coupling of a continuous liquid-liquid extractor to a flame atomic absorption spectrometer for the determination of alkaloids. M. Eisman, M. Gallego and M. Valcfircel. The possibility of using classical reagents as Dragendorff's and Co(SCN)42- is investigated for the indirect determination of amylocaine, papaverine and bromhexine hydrochloride using a continuous extraction system and measurement of bismuth and cobalt in the organic phase (1,2-dichloroethane) by flame atomic absorption spectrometry. The method thus developed permits the determination of the three alkaloids over a wide concentration range (0.5-175 gg ml-1), with a relative standard deviation of approximately 3%. - J. Anal. At. Spectrom. 7, 1295-1298 (1992). Dept. Anal. Chem., Fac. Sci., Univ., E-14004 C6rdoba Voltammetric determination of total alkannin using a glassy carbon electrode. R. Chaisuksant, A. Voulgaropoulos, A.S. Mellidis and V.P. Papageorgiou. A sensitive voltammetric method was developed for the determination of isohexenylnaphthazarines as total alkannin after appropriate alkaline hydrolysis using a glassy carbon electrode and 0.01 M tetraethylammonium tetrafluoroborate in dimethylforrnamide as supporting electrolyte. The method was applied to the determination of total alkannin in the roots of Alkanna tinctoria. The detection limit was 0.55 mg 1 1 and the relative standard deviation 2.29%. For the accuracy of the method the hydrolysis step was crucial. - Analyst 118, 179-182 (1993). Anal. Chem. Lab., Chem. Dept., Aristotle Univ., GR-54006 Thessaloniki Determination of some narcotic and toxic alkaloidal compounds by overpressured thin-layer chromatography with ethyl acetate as eluent. J. Pothier, N. Galand and C. Viel. Various chemical classes of alkaloids can be separated by overpressured thin-layer chromatography (OPTLC) on aluminium oxide plates with ethyl acetate alone as the mobile phase. The OPTLC method is efficient, rapid (15 rain) and combines the advantages of classical TLC and HPLC. Most commonly used narcotic and toxic agents can be separated with this method. For cannabinoids (narcotic phenolic compounds), the characterization requires the use of a binary eluent [hexaneethyl acetate (70: 30, v/v)]. - J. Chromatogr. 634, 356 - 359 (1993). Lab. Pharm. Chim. Prod. Nat., Fac. Pharm., 37042 Tours Cedex (F) Flnorometric assay using dimeric dyes for double- and single-stranded DNA and RNA with pieogram sensitivity. H.S. Rye, J.M. Dabora, M.A. Quesada, R.A. Mathies and A.N. Glazer. Two compounds of the new class of highly fluorescent dimeric asymmetric cyanine dyes, which possess a very high affinity to nucleic acids, are investigated. The thiazole organge homodimer (TOTO) and the oxazol yellow homodimer (YOYO) bind with more than a 1000-fold fluorescent enhancement upon binding. In the concentration range from 0.5 to 100 ng DNA/ml a linear dependence fluorescence intensity has been observed in the presence of 2 x 10 7 tool/1 TOTO or YOYO in 4 mmol/1 Tris-acetate/0.1 mmol/1 EDTA/50 mmol/1 NaCI (pH 8.2). This allows sensitive quantitation of double-stranded DNA in a conventional fluorometer. As little as 20 pg of double-stranded DNA can be detected with the array scanning method which is rapid, has high throughput, and requires small amounts of sample. -- Anal. Biochem. 208, 144150 (1993). Dept. Mol., Cell Biol., Univ., Berkeley, CA 94720 (USA) Selective determination of triphosphonucleotide by a flow injection/chemiluminescence method. Y. Ohno, T. Hobo, R. Tamura and M. Ishii. Highly selective determination of triphosphonucleotide such as adenosine triphosphate (ATP) was established by a flow injection method with chemiluminescent detection of 1,10-phenanthroline. The high selectivity is obtained by loading triphosphonucleotide such as ATP chemically to copper(II)-modified clinoptirolite (zeolite). The analyte is indirectly determined by a CL detection of copper(II) eluted from Cu-Zeo through a material exchange between Cu-Zeo and analyte. The system is comprised of three flow lines, and one of them has the material

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Biochemical and clinical analysis

exchange column packed with the Cu-Zeo of 2.4 g. The limits of determination by 100 gl injection method were 50 fmol to 2.0 pmol for ATP, 60 fmoI to 1.0 pmol for uridine triphosphate, 50 fmol to 3.0 pmol for guanosine triphosphate and 80 fmol to 1.0 pmol for cytidine triphosphate. The relative standard deviation was 2.1% in 5 repeated runs of 1 x 10 .9 M ATP. The selectivity was high and the CL intensity of 1 x 10 -9 M ATP alone was not interfered by coexistence of 1 x 10 .4 M other nucleotides and their derivatives. The present method was also successfully applied to determine number of bacteria in normal human urine. - Bunseki Kagaku 42, 183 - 190 (1993). (Orig. Jap.). Cosmo Res. Inst., 1134-2, Gongendo, Satte-shi, Saitama 340-01 (J) Liquid chromatographic separation of monoamino analogues of dideoxyadenosine and 9-(dideoxy-fl-D-lyxo-pentofuranosyl)-adenine from adenine. G. Thoithi, A. Van Schepdael, P. Herdewijn, E. Roets and J. Hoogmartens. A liquid chromatographic method that can separate each of the monoamino analogues of dideoxyadenosine and 9(dideoxy-~-D-lyxopentofuranosyl)adenine from their main degradation product, adenine, is carried out on a 10 gm Spherisorb ODS1 column (250 mm x 4.6 mm I.D.) using acetonitrile/0.2 M potassium phosphate buffer pH 6.0/0.2 M tetramethylammonium phosphate pH 6.0/water (5:5:0.5 : 89.5, v/v) as the mobile phase. - Chromatographia 35, 451 - 4 5 4 (1993). Kath. Univ. Leuven, Lab. Farm. Chem., Inst. Farm. Wet., Van Evenstraat 4, 3000 Leuven (B) Fluorescence detection and size measurement of single DNA molecules. A. Castro, F.R. Fairfield and E. Brooks Shera. To detect single DNA molecules in a hydrodynamically focused flowing solution double-stranded )~DNA molecules at 3 x 10 is M were stained with the fluorescent dye TOTO-1 and were individually detected. The technique makes use of a frequency-doubled mode-locked Nd: YAG laser to repetitively excite the molecules as they traverse the tightly focused laser beam. The flowing sample solution was hydrodynamically focused down to a 20-gm-diameter stream by a rapidly flowing water sheath. The ermitted fluorescence photon burst originating from a single DNA molecule was detected with a microchannel plate photomultiplier based single-photon counter, which used time-gated electronics for Raman and Rayleigh scattering rejection. A mixture of )~ DNA and smaller single-cut fragments has been simultaneously detected and identified by size. The detection of full length duplex )~phage DNA molecules (48, 502 base pairs) is possible with this technique. - Anal. Chem. 65, 849-852 (1993). Biophys. Theoret. Biol. Groups, Los Alamos Nat. Lab., Los Alamos, NM 87545 (USA) A laecase electrode for organic-phase enzymatic assays. J. Wang, Y. Lin, A.V. Eremenko, A.L. Ghindilis and I.N. Kurochkin. The biocatalytic activity of laccase from Coriolus hirsutus in nonaqueous environments is exploited for developing an organic-phase amperometric biosensor. As useful for stable immobilization of the enzyme has proven the Eastman-AQ ionomer. The electrode responds rapidly to low concentrations of catechols and hydroquinone in various alcohols. The detection limit for hydroquinone is 6 x 10 -7 M. Various experimental variables, influencing the response of the organic-phase biosensor, are explored. With flow injection, 60 samples per hour can be processed with a relative standard deviation of 1.3%. - Anal. Lett. 26, 197--207 (1993). Dept. Chem., New Mexico State Univ., Las Cruces, NM 88033 (USA) Photoelectrochemical sensor for catalase activity based on the in situ generation and detection of substrate. C.B. Cohen and S.G. Weber. The sensitivity of peroxide-containing solutions to catalase is determined. A device for the in situ generation and detection of hydrogen peroxide is presented for application to the automation of enzyme immunoassay and application to biosensors. The device is fabricated from a gold-coated optical fiber. It photochemically generates and electrochemically detects H2Oz in aqueous, buffered solutions. The electrochemical signal is attenuated in the presence of the enzyme catalase (EC 1.tl.l.6), for which H202 is a substrate. The sensor's photosignal is reduced by 50% in the presence of 25 nM catalase. Detection limits of

3 Biochemical and clinical analysis 76 pM catalase have been obtained using FIA. - Anal. Chem. 65, 169 175 (1993). Dept. Chem., Univ., Pittsburgh, PA 15260 (USA)

A new enzymatic determination of ornithine carbamoyltransferase activity. K. Isobe, T. Matsuzawa and Y. Nagamura. A new enzymatic assay method for ornithine carbamoyltransferase, OCT, activity was developed using ornithine:2-oxo-acid aminotransferase and l-pyrroline-5-carboxylate dehydrogenase. The method is based on the reaction of L-ornithine formation from L-citrulline by OCT. OCT shows its maximum activity around pH 8.0. The OCT activity was measured spectrophotometrically at 340 nm and the minimum detectable activity was about 4 units/1 of serum. Results obtained by this method and by the chemical method correlated well. The method does not require boiling of the reaction mixture nor removal of interfering substances in the serum. - Anal. Lett. 26, 475-486 (1993). Res. Developm. Div., Amano Pharm. Co., Nishikasugai-gun, Aichi 481 (J) A high-performance liquid chromatography assay for threonine/serine dehydratase. B.K. Singh, I. Szamosi and D. Shaner. A novel HPLC assay for threonine dehydratase is described that is based on the derivatization of the 2-keto acids produced by the enzyme using a specific derivatization agent, o-phenylenediamine, and fluorimetric detection after HPLC as low as 5 pmol keto acid could be detected. This assay is over 1000-fold more sensitive than the commonly used dinitrophenyi hydrazine derivatization assay. - Anal. Biochem. 208, 260-263 (1993). American Cyanamid Company, Princeton, NJ 085430400 (USA)

Solvent system selection for separation of anthraquinones by means of centrifugal partition chromatography. Application to an extract of a Rubia tinctorum hairy root culture. A.C.J. Hermans-Lokkerbol, R. van der Heijden and R. Verpoorte. CPC is a useful, fast and mild technique for the separation of anthraquinones, which can be performed on analytical and preparative scale. A major advantage is that both glycosides and aglycones can be separated in one run. The two systems n-hexane-EtOAc-MeOH-water 9 : 1 : 5 : 5 v/v/v/v and chloroform-MeOH-water-aceticacid 5 : 6:4: 0.05 v/ v/v/v offer different selectivity. - J. Liquid Chromatogr. 16, 1433-1451 (1993). Div. Pharm., Cent. Bio-Pharm. Sci., Gorlaeus Lab., Leiden University, 2300 RA Leiden (NL)

Determination of thromboxane B2 by normal-phase high-performance liquid chromatography after pre-colamn derivatization with fluorescent reagents. R. Ben Gueddour, M. Matt, A. Nicolas, M. Donner and J.F. Stoltz. Thromboxane B2 produced in vitro by human platelets under pharmacological stimulation was determined by HPLC after pre-column derivatization with fluorescent probes. The carboxylic group of thromboxane B2 was esterified either by 4-bromomethyl-7-methoxycoumarin or by panacyl bromide whereas its alcoholic functions were derivatized using 7-[(chlorocarbonyl)methoxy]-4-methylcoumarin. The fluorescent esters obtained were chromatographed on a normal phase column (LiChrosorb Diol 5 gin) with hexane-ethanol (80:20, v/v or 90:10, v/v) and detected fluorescence. - Anal. Lett. 26, 429 - 4 4 3 (1993). Lab. Chim. Anal., URA CNRS 597, Fac. Sci. Pharm. Biol., 54001 Nancy Cedex (F)

223 reagents. The detection limits (S/N = 3) for the indoles were in the range i40 470 fmol per injection volume (100 gl). The method was applied to the determination of 5-hydroxyindol-3-ylacetic acid in human urine, with direct sample injection. - Analyst 118, 165-169 (1993). Fac. Pharm. Sci., Fukuoka Univ., Johnan-ku, Fukuoka 814-01 (J)

Determination of dextromethorphan and dextrorphan in urine by capillary zone electrophoresis: Application to the determination of debrisoquinoxidation metabolic phenotype. S. Li, K. Fried, I.W. Wainer and D.K. Lloyd. A simple capillary zone electrophoretic method is proposed for the direct determination of dextromethorphan and its metabolite, dextrorphan, in urine without any sample pretreatments. A linear reiationship was observed between the peak area and the concentration of both dextromethorphan and dextrorphan within the range of 490 ng ml 1 to 500 ~g ml- 1 with a correlation coefficient ofgreater than 0.9999. The limit of detection was 80 ng ml- 1 for both compounds. The interday coefficients of variation for the concentrations of 2.5 ~tg ml- a and 50 ~tg ml -~ were 6.2% and 4.1% for dextromethorphan, and 5.6% and 2.8% for dextrorphan (n= 15). - Chromatographia 35, 216-222 (1993). Dept. Oncol., McGill Univ., McIntyre Med. Build., 3655 Drummond, Montreal, Quebec (CDN)

Direct enantiomeric analysis of amphetamine in plasma by simultaneous solid phase extraction and chiral derivatization. F.-X. Zhou and I.S. Krull. A one step determination of enantiomeric amphetamine composition in plasma is described which is based on the direct injection of the plasma sample onto the solid phase reagent and subsequent reversed phase HPLC separation. The protein compounds were excluded by the small pore structure of the polymer column and washed out of the reaction column before derivatization. Spiked amphetamine in human plasma was extracted and derivatized by the polystyrene based FMOC-L-proiyl solid phase reagent. The derivatized diastereomers were separated on a conventional ODS column with an ACN/H20 mobile phase. Calibration plots and reproducibility experiments were performed. Automation of the procedure provided a. simple and reproducible method for direct chiral recognition in plasma samples. Linearity is obtained from 0.15 to 10 gg/ml for each enantiomer. - Chromatographia 35,153 - 159 (1993). Dept. Chem., The Barnett Inst., 341 MU, Northeastern Univ., Boston, MA 02115 (USA)

High-performance liquid chromatography coupled to high-field proton nuclear magnetic resonance spectroscopy: Application to the urinary metabolites of ibuprofen. M. Spraul, M. Hofmann, P. Dvortsak, J.K. Nicholson and I.D. Wilson. The applicability of coupled HPLC-NMR for the detection and identification of the urinary metabolites of ibuprofen is described. Analysis was performed on both a freeze-dried urine concentrate and partialy purified extracts obtained by solid-phase extraction onto C-18 bonded silica gel. Both continuous and stop-flow methods were used to obtain spectra enabling the major urinary metabolites of ibuprofen to be detected and identified. HPLC-NMR is not so sensitive as HPLC/MS but for tasks like the described one absolutely adequate. Anal. Chem. 65, 327-330 (1993). Bruker Anal. MeBtechnik, Silberstreifen, W-7512 Rheinstetten (D)

High-performance liquid chromatographic determination of 5-hydroxyindoles by post-column fluorescence derivatization. J. Ishida, R. Iizuka and

Ascorbate and dehydroascorbate measurements in aqueous solutions and plasma determined by gas chromatography-mass spectrometry. J.C.

M. Yamaguchi. A selective and sensitive high-performance liquid chromatographic method with post-column fluorescence detection has been developed for the determination of 5-hydroxyindoles and can be applied to the determination in urine without prior sample purification. Only 5 ~tl samples are required. Five biogenic 5-hydroxyindoles (5hydroxytryptophan, 5-hydroxytryptamine, 5-hydroxyindol-3-ylacetic acid, 5-hydroxytryptophoI and N-acetyl-5-hydroxytryptamine) were separated by isocratic elution with acetonitrile/10 mM acetate buffer (pH 4.7) (5:59) as mobile phase on a reversed-phase column, TSKgel ODS-80Tm, and then converted into fluorescent derivatives by postcolumn reaction with benzylamine and potassium hexacyanoferrate(III)

Deutsch and J.F. Kolhouse. Ascorbic acid and dehydroascorbic acid can be determined in human blood plasma as their tert-butyldimethylsilyl derivatives by GC/MS, and an isotope dilution assay for ascorbate and dehydroascorbate is described using [13C6]ascorbic acid and [13C6]- and [6,6-2H2]dehydro ascorbate. GC was carried out on a SPB-I fused silica capillary with a temperature program from 80 to 300°C, and MS was used in the EImode. This assay was used to monitor ascorbic acid loss and the resulting rise of dehydroascorbic acid in aqueous solutions and plasma. - Anal. Chem. 65, 321-326 (1993). Div. Gast. Hematol., Dept. Med., Dept. Vet. Aft. Hosp., Univ. CoIorado Health Sci. Cent., Denver, CO 80262 (USA)

224 Determination of phosphatidylcholine hydroperoxide in plasma and serum by HPLC[postcolumn method. K. Akasaka, K. Morimune, H. Ohrui, H. Meguro and M. Ohta. Phosphatidylcholine hydroperoxidase (PC-HPO) in human plasma and bovine serum was separated by HPLC on a silicagel column eluted with chloroform/methanol/water followed by postcolumn reaction with a fluorescence reagent, diphenyM-pyrenylphosphine. PC-HPO was determined at the range of 1 ~ 650 pmol and the detection limit was I pmol (S/N-3). The relative standard deviation of the peak area was 1.8% (108 pmol, n = 7 ) and 3.4% (21.6 pmoi, n=7). PC-HPO in biological fluids were extracted twice with methanol/dichloromethane.Phosphatidylcholine, [3-NBD-aminohexanoyl-7-palmitoyl, was added as an internal standard detected by UV at 475 nm. The relative standard deviation was 6.5%. Recovery of PC-HPO from human plasma was 84.3%. PC-HPO was determined as 30~ 75 nM (n= 13) in human plasma, and 9 ~ 100 nM (n=67) in bovine serum. - Bunseki Kagaku 42, 27-31 (1993). (Orig. Jap.) Dept. Appl. Biol. Chem., Fac. Agricult., Tohoku Univ., Sendai-shi, Miyagi 981 (J) Simultaneous HPLC determination of free, conjugated, and sulfated bile acids. J.H. Nichols, R.D. Ellefson, J. Hermansen, K. Schifferdecker and M.F. Burritt. To separate the 18 major bile acids in a single analytical run the bile acids are rapidly extracted from bile, urine or peritoneal fluid over a C18 cartridge and resolved on a reverse-phase column. A gradient of 66 to 90% methanol in sodium acetate (30 raM, pH 3.4) was used as mobile phase. Peaks at 210 nm are quantitated by comparison with the peak area of commercial standards. Standard regression lines are linear over the range of 2 - 4 0 gg for conjugated acids and 50-800 gg for unconjugated acids (correlation coefficient range, r=0.962 to 0.989; coefficient of variation, CV = 7.8 %). Limits of detection are 1 and 20 gg respectively. - J. Liquid Chromatogr. 16, 681-697 (1993). Dept. Lab. Med. and Path., Rochester, MN 55905 (USA) Determination of erythromycin in human plasma and whole blood by high-performance liquid chromatography. Y. Kato, T. Yokoyama, M. Shimokawa, K. Kudo, J. Kabe and K. Mohri. A simple, selective, sensitive, and rapid HPLC method is described for the quantitation of erythromycin (EM) in plasma and whole blood.

3

Biochemical and clinical analysis

0.2 ml blood samples were treated with oleandomycin phosphate as internal standard, saturated Na2COa solution and extracted with diethyl ether. The residue of the evaporated organic extract was reconstituted in mobile phase and analysed on a ODP polymer column with 50 mM KH2PO4 (pH 10.5)/acetonitrile (63:37) as mobile phase and electrochemical detection. Analytical recovery of EM at concentrations of 0.2, 1.0 and 5.0 gg/ml was > 75%. The coefficients of variation (CVs) for intra- and inter-day assay reliabilities at 0.2, 1.0 and 5.0 gg/ml of EM were < 5.8% in plasma and < 6.3% in whole blood, respectively. The calibration curves for the respective analyte were linear (r = 0.994) over concentration ranging from 0.1 to 5.0 ~tg/ml in plasma and whole blood. The lower detection limit for EM in plasma and whole blood was 0.1 gg/ml (CVs <5.3%). - J. Liquid Chromatogr. 16, 661-680 (1993). Dept. Pharm., Nat. Med. Center Hosp., Shinjuku-ku, Tokyo 162 (J)

Quantitative HPTLC in toxicology. H. Schiitz and F. Erdmann. HPTLC is a valuable tool for qualitative and quantitative analysis of many compounds which are frequently encountered in toxicological analysis. Thin layer-scanners can be used for the quantitative determination of opiates (esp. 6-monoacetylmorphine as heroin marker), 1,4benzodiazepines via aminobenzophenones, phenothiazines, doping agents, barbiturate derivatives and pesticides. Special ranges of application are discussed as investigations in traffic and working places. GIT Fachz. Lab. 37, 1 8 - 2 2 (1993). Inst. Rechtsmedizin, Univ., GieBen (D) R.H.S. Toxin detection using a tyrosinase-coupled oxygen electrode. M.H. Smit and G.A. Rechnitz. An enzyme-coupled oxygen electrode is created which is sensitive to selective poisoning. Biocatalytic reduction of oxygen is promoted by electrochemically supplying tyrosinase with electrons. Thus, ferrocyanide is generated at a cathode and mediates the enzymatic reduction of oxygen to water. An enzyme-dependent reductive current can be monitored which is inhibited by cyanide in a concentration-dependent manner. Enzyme activity is electrochemically initiated and terminated and the sensor becomes capable of continuous monitoring. Cyanide poisoning of the biological component is reversible, and it can be reused after rinsing. The resulting sensor detects cyanide based on its biological activity. - Anal. Chem. 65, 380-385 (1993). Hawaii Biosensor Lab., Dept. Chem., Univ. Hawaii, Honolulu, HI 96822 (USA)