Food Anal. Methods DOI 10.1007/s12161-016-0678-0
Screening of Over 600 Pesticides, Veterinary Drugs, Food-Packaging Contaminants, Mycotoxins, and Other Chemicals in Food by Ultra-High Performance Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry (UHPLC-QTOFMS) Patricia Pérez-Ortega 1 & Felipe J. Lara-Ortega 1 & Bienvenida Gilbert-López 2 & David Moreno-González 1 & Juan F. García-Reyes 1 & Antonio Molina-Díaz 1,3
Received: 12 July 2016 / Accepted: 28 September 2016 # Springer Science+Business Media New York 2016
Abstract In this article, an accurate mass multiresidue screening method has been developed for the determination of over 630 multiclass food contaminants in different matrices using ultra-high performance liquid chromatography/(quadrupole)-time-of-flight mass spectrometry. The compounds included in the study were 426 pesticides, 117 veterinary drugs, 42 food-packaging contaminants, 21 mycotoxins, 10 perfluorinated compounds, 9 nitrosamines, and 5 sweeteners. The separation was carried out by liquid chromatography using a C18 column (50 mm × 2.1 mm, 1.8 μm particle size). The identification of the targeted species was accomplished using accurate masses of the targeted ions (protonated or deprotonated molecule) along with retention time data and characteristic fragment ion for reliable identification, using specific software for automated data mining and
exploitation. The performance of the screening method was validated in terms of linearity, matrix effect, and limits of quantification for three representative food matrices (tomato, orange, and baby food) using a generic sample treatment based on liquid partitioning with acetonitrile (QuEChERS). The overall method performance was satisfactory with limits of quantification lower than 10 μg kg −1 for the 44 % of studied compounds. In some cases (ca. 10–15 % of the pesticides depending on the matrix tested, maximum residue levels were not fulfilled). In orange, 15 % of the compounds displayed LOQs above the maximum residue levels (MRLs) set for the studied pesticides, which can be partially attributed to matrix effects. Moderate signal suppression was observed in the three matrices tested in most cases, being orange the matrix which produced the highest matrix effect and baby food the lowest one.
Electronic supplementary material The online version of this article (doi:10.1007/s12161-016-0678-0) contains supplementary material, which is available to authorized users.
Keywords Screening method . Organic contaminants . Matrix effect . Liquid chromatography-mass spectrometry . Foodstuffs
* Antonio Molina-Díaz
[email protected] 1
Analytical Chemistry Research Group, Department of Physical and Analytical Chemistry, University of Jaén, Campus Las Lagunillas, Edif. B-3, 23071 Jaén, Spain
2
Foodomics Laboratory, Bioactivity and Food Analysis Department, Institute of Food Science Research - CIAL (UAM+CSIC), Campus de Cantoblanco, Calle Nicolás Cabrera 9, 28049 Madrid, Spain
3
Center for Advanced Studies in Olives Grove and Olive Oils (CEAOAO), Science and Technology Park GEOLIT, 23620 Mengíbar, Spain
Abbreviations CCL-3 Contaminant candidate lists CID Collision-induced dissociation GC-MS/ Gas chromatography/tandem mass MS spectrometry HRMS High-resolution mass spectrometry LC-MS/MS
Food Anal. Methods
MeOH QC QuEChERS
Liquid chromatography/tandem mass spectrometry Methanol Quality control Quick, easy, cheap, effective, rugged, and safe
Introduction Food quality and safety have become of increasing concern for consumers, governments, and producers in such globalized market, where commodities are produced and distributed throughout the world (Malik et al. 2010; Di Stefano et al. 2012). Food chemical contaminants have been defined as Bany chemical not intentionally added to food but present from many potential sources,^ including residues from the application of pesticides and veterinary medicines, those entering the food chain from the environment, and those formed during the processing of food, natural toxins, accidental contamination, or adulteration (Hird et al. 2014). To protect the health of consumers, stringent regulations enforced with diligent monitoring of foods have been recently established. The need of methods covering multiclass contaminants such as pesticides, veterinary drugs, and mycotoxins is illustrated by selected recent examples in the literature (Zhan et al. 2012; Mol et al. 2008; Garrido Frenich et al. 2014; FerrerAmate et al. 2010; Pérez-Ortega et al. 2012; Gómez-Pérez et al. 2015). For instance, derivate food products such as baby food combine different matrices: cereal-based food, meat-based food, powdered milk-based infant formulae, and fruit- and vegetable-based food (European commission 2006a). Consequently, they should be tested keeping in mind the potential simultaneous presence of both pesticides and veterinary drugs. Other contaminants such as parabens, human pharmaceuticals and antibiotics, and veterinary drugs have been recently reported in processed food (Fussell et al. 2014) due to contamination either during farming/crop production—as the use of reclaimed water is becoming more common (Matamoros et al. 2012)—or in the food-producing scenarios. Furthermore, contaminants can also enter the food chain through adulteration of food (international contamination, e.g., melamine in milk formulae) (Langman 2009). To cope with these outstanding numbers of contaminants/commodity combinations, laboratories must use multiresidue strategies. The monitoring of residues from either pesticides or other contaminants in products of both plant and animal origin is of great interest for the protection of human health. It is currently addressed by means of a plethora of regulations worldwide (EPA 2016; European Commission 2005; US Department of Agriculture 2014; European Commission 2010; US Food Drug Administration 2011; European Commission 2006b; Canadian Food Inspection Agency 2016; European Commission 2016; Health Canada 2014; National Standard
GB-2763 2014; Codex Alimentarius 2016). Laboratories monitoring these chemicals must have cost-effective, rapid, and comprehensive methods for detecting their presence. Current food safety methods are aimed at the simultaneous determination of several families of contaminants and/or residues. These methods increase sample throughput and the capabilities of routine laboratories (Malik et al. 2010; Di Stefano et al. 2012; Hird et al. 2014; Picó et al. 2015). The standard method for determining pesticides, veterinary drugs, and other relevant contaminants, namely multiresidue method, is a targeted approach based on multiple reaction monitoring (MRM) acquisition, using liquid chromatography/tandem mass spectrometry (LC-MS/MS) or/and gas chromatography/ tandem mass spectrometry (GC-MS/MS) (Gilbert-López et al. 2010). However, the main flaw of the approach is the previous knowledge required to set up the acquisition method (retention time and optimized MS/MS transitions for each analyte sought). Consequently, LC-MS/MS multiresidue methods are blind to compounds not defined in the MRM method, so that none or scarce information on possible non-target or unknown pesticides or their degradation products are available when using these techniques. Multiresidue methods also require dedicated validation and quality control (QC) (due to the large number of species). In quantitative multiresidue methods, valuable time and effort are wasted in generating ongoing QC data for many compounds that are not frequently detected. Therefore, screening methods skipping such reference materials and all ongoing QC measurements associated are desirable. Liquid chromatography combined with high-resolution mass spectrometry (LC-HRMS) has shown to be an effective approach to screen food samples for the presence of high number of analytes. In contrast to low-resolution MS/MS acquisition, LC full-scan HRMS enables a fully untargeted measurement with the ability to retrospectively detect additional compounds in the raw data, which were not anticipated to be of interest at the time of sample analysis (Gómez-Ramos et al. 2013; Mezcua et al. 2009; Polgar et al. 2012; Díaz et al. 2011; Pérez-Ortega et al. 2016). Although the interrogation of the data is performed against the list of compounds included in the database or library, retrospective evaluation is always possible as data for all compounds that have given sufficient detector response is acquired (Gómez-Ramos et al. 2013; Mezcua et al. 2009; Polgar et al. 2012; Díaz et al. 2011). The development of accurate mass LC-HRMS screening methods has been addressed by different authors, using either time-of-flight (Mezcua et al. 2009; Polgar et al. 2012; Díaz et al. 2011; García-López et al. 2014; Lacina et al. 2010; Wang et al. 2014) or Orbitrap mass spectrometers (Gómez-Pérez et al. 2015; Alder et al. 2011). These methodologies include typically between 200 and 450 pesticides, although there are also a few examples covering other contaminants such as veterinary drugs (Masía et al. 2016, Picó et al. 2015, RomeroGonzález et al. 2011). Hybrid mass spectrometers performing
Food Anal. Methods
MS/MS acquisition of product ions at high resolution provide additional structural information for identification purposes, enabling the discrimination among isobaric or isomeric species and the discovering of metabolites or degradation pathways. In this article, an accurate mass multiresidue screening method using ultra-high performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOFMS) has been developed and its performance evaluated for over 600 multiclass food contaminants (pesticides, veterinary drugs, mycotoxins, nitrosamines, perfluorinated compounds, sweeteners, and food-packaging contaminants) in food, using tomato, orange, and baby food as model matrices.
Experimental Section Chemicals and Reagents Pesticides, veterinary drugs, foodpackaging contaminants, perfluorinated compounds, mycotoxins, nitrosamines, and sweeteners of analytical grade standards were purchased from Fluka (Pestanal quality) (Madrid, Spain), Sigma-Aldrich (Madrid, Spain), or Dr. Ehrenstorfer (Augsburg, Germany). Individual stock solutions (ca. 500 mg L−1 each) were prepared in different solvents depending on compound solubility and stability (acetonitrile, methanol (MeOH), and/or water in basic or acidic media) and were stored at −20 °C. Working solutions containing ca. 30 compounds each were prepared by appropriate dilution of the stock solutions with MeOH at 10 mg L−1. HPLC-grade acetonitrile and MeOH were obtained from Merck (Darmstadt, Germany). Formic acid was obtained from Fluka (Buchs, Switzerland). Primary-secondary amine (PSA) Bond Elut was obtained from Varian, Inc. (Palo Alto, CA, USA). Acetic acid was from Panreac (Barcelona, Spain). Anhydrous magnesium sulfate anhydrous (MgSO4) and sodium acetate (NaCOOCH3) were from Sigma-Aldrich (Madrid, Spain). A Milli-Q-Plus ultrapure water system from Millipore (Milford, MA, USA) was used throughout the study to obtain the HPLC-grade water used during the analyses. Selection of the Studied Compounds The 630 compounds included in the screening method were carefully selected considering different lists established by official bodies from the European Union and the USA, previous relevant literature, and thus their potential presence in different types of foodstuffs and water. Up to 426 pesticides, 117 veterinary drugs and pharmaceuticals, 42 food-packaging contaminants, 10 perfluorinated compounds, 21 mycotoxins, 9 nitrosamines, and 5 sweeteners were included. From the 426 pesticides included, most of them are covered in Annex 1 of Directive 396/2005 for several commodities (European Commission 2005). A significant number (over 130 species), of priority pesticides (according to Annex I of Commission Implementing Regulation 788/2012 due to their usage and frequency of detection), were also included in the
targeted list (Gallart-Ayala et al. 2013). Most of the selected food-packaging contaminants and perfluorinated compounds are regulated by different documents (European Commission 2012; Gallart-Ayala et al. 2013; European Commission 2011; FDA 2016; European Commission 2006b; EPA 2009, 2015; European Commission 2015). With regards to the veterinary drugs and pharmaceuticals, most of the selected substances are US FDA-approved veterinary drugs for animal use (FDA 2016) or authorized products in the European Union. It should be noted that some of the species are included in Table 1 as pesticides, although they can be also classified as veterinary drugs such as albendazole, fenbendazole, fenthion, ivermectin, lufenuron, spinosad, sulfaquinoxaline, thiabendazole, and trichlorfon, all of them included in US FDA-approved list for animal use. Along with the veterinary drugs, other human pharmaceuticals were included due to their ubiquitous presence in the environment. Besides, all the main mycotoxins including those regulated in Commission Regulation EC 1881/2006 (European Commission 2006b) are among those 21 substances selected. The nine nitrosamines selected are included in US EPA final Drinking Water Contaminant Candidate lists (CCL-3) (EPA 2009, 2015). Finally, all the sweeteners included are SANTEauthorized food additives (European Commission 2015). Sample Treatment Different baby food samples from different local markets containing meat and vegetables were pooled and used as model matrix, along with tomato and orange. Extraction was accomplished using QuEChERS approach (Lehotay 2011). A representative 10-g portion of homogenized sample was weighed in a 50-mL plastic centrifuge tube and mixed with 10 mL of 0.1 % acetic acid in acetonitrile, being the tube vigorously shaken for 1 min. Then, 1 g of NaCOOCH3 and 4 g of MgSO4 anhydrous were added, and the tube was shaken again to prevent coagulation of MgSO4. The extract was centrifuged (1464 rcf) for 3 min. A 5-mL aliquot of supernatant (acetonitrile phase) was taken with a pipette and transferred to a 15-mL centrifuge tube containing 250 mg of PSA and 750 mg of MgSO4 anhydrous that was energetically shaken for 20 s. The extract was centrifuged again (1464 rcf) for 3 min. Three milliliters of supernatant were taken and evaporated to near dryness and reconstituted to 3 mL of 20 % MeOH. Prior UHPLC-MS analysis, the extract was filtered through a 0.45-μm PTFE filter and transferred into a vial. These extracts were used for method performance evaluation by appropriate spiking with the compound mixtures. Ultra-High Performance Liquid ChromatographyElectrospray-Quadrupole-Time-of-Flight Mass Spectrometry The separation and identification of the analytical standards were carried out using a reversed phase C18 column (50 mm × 2.1 mm and 1.8 μm particle size, Zorbax Rapid Resolution High Definition (RRHD) Eclipse-Plus C18) by means of an Agilent UHPLC system (Agilent 1260,
Food Anal. Methods Table 1 Accurate mass database of the studied pesticides, veterinary drugs, food-packaging contaminants, mycotoxins, perfluorinated compounds, nitrosamines, and sweeteners, including elemental composition, retention time (tR), theoretical and experimental m/z values, and error (ppm) for the main ion of each compound in baby food extracts (50 μg kg−1) Compound
Elemental composition (M) tR (min) Ion
Theoretical m/z Experimental m/z Error (ppm)
Pesticides 1-Naphtalene-acetamide 1-Naphtyl-methylcarbamate 2,4-Dichlorophenoxy acetic acid 2,4-Dinitrophenol 3,3-Dichlorobenzidine 3,5-Dichloroaniline 4-Chloro-2-methylphenol 4-Chloro-o-tolyoxyacetic acid
C12H11NO C12H15NO3 C8H6Cl2O3 C6H4N2O5 C12H10Cl2N2 C6H3NH2Cl2 C7H6N2O5 C9H9ClO3
4.28 4.83 5.10 4.58 5.61 5.52 5.10 5.11
C11H9+ C10H13O2+ [M-H]− [M-H]− [M+H]+ [M+H]+ [M-H]− C7H6ClO−
141.0699 165.0910 218.9621 183.0047 253.0294 161.9872 141.0113 141.0113
141.0698 165.0912 218.9621 183.0049 253.0291 161.9871 141.0114 141.0131
-0.71 1.21 0.00 1.09 -1.19 -0.62 0.71 -2.84
Acephate
C4H10NO3PS C10H11ClN4 C8H6N2OS2 C12H9ClN2O3 C14H20ClNO2 C12H15N3O2S C7H14N2O2S C7H14N2O4S C7H14N2O3S C19H26O3 C19H26O3 C9H17N5S C11H16N2O2 C19H23N3 C2H4N4 CH6NO3P C9H5Cl3N4 C13H19ClNO3PS2
0.81 3.96 5.69 6.31 6.14 4.42 4.30 2.71 1.61 7.11 7.07 4.35 0.96 7.10 0.27 0.34 5.82 6.46
C2H9O3PS+ [M+H]+ [M+H]+ [M+H]+ C11H16N+ [M+H]+ [M+H]+ C4H8NO+ C4H9S+ C9H11O+ C9H11O+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M-H]− [M-H]− [M+H]+
142.9926 223.0745 210.9994 265.0374 162.1277 266.0958 213.0668 86.0600 89.0419 135.0804 135.0804 228.1278 209.1285 294.1965 85.0509 110.0013 272.9507 368.0305
142.9927 223.0745 210.9994 265.0378 162.1276 266.0959 213.0667 86.0603 89.0422 135.0803 135.0807 228.1278 209.1287 294.1970 85.0509 110.0015 272.9509 368.0308
0.70 0.00 0.00 1.51 -0.62 0.38 -0.47 3.49 3.37 -0.74 2.22 0.00 1.01 1.70 0.00 1.82 0.73 0.82
C8H10N2O4S C8H14ClN5 C6H10ClN5 C5H8ClN5 C12H11Cl2N3O2 C9H10ClN2O5PS C12H16N3O3PS2 C10H12N3O3PS C12H10N2 C20H35N3Sn C22H17N3O5 C11H9Cl2NO2 C20H23NO3 C11H13NO4 C13H16F3N3O4 C20H30N2O5S C16H18N4O7S C14H24NO4PS3
2.23 4.95 3.73 3.08 5.04 4.63 6.20 5.65 5.55 6.73 5.78 6.04 6.35 4.80 7.29 7.05 5.37 6.49
C6H6NO2S+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+Na]+ C8H6NO+ [M+H]+ [M-C2H2N3]+ [M+H]+ C10H9ClN+ [M+H]+ C9H11O3+ [M+H]+ [M+H]+ [M+H]+ C8H13NO4PS3+
156.0114 216.1011 188.0697 174.0541 300.0301 324.9809 368.0263 132.0444 183.0917 369.1604 404.1241 178.0418 326.1751 167.0703 336.1166 411.1948 411.0969 313.9739
156.0115 216.1010 188.0699 174.0542 300.0298 324.9807 368.0261 132.0441 183.0916 369.1598 404.1245 178.0420 326.1752 167.0705 336.1173 411.1947 411.0968 313.9740
0.64 -0.46 1.06 0.57 -1.00 -0.62 -0.54 -1.51 -0.55 -1.63 0.99 1.12 0.31 1.20 2.08 -0.24 -0.24 0.32
C10H12N2O3S C12H12N2
4.97 0.43
[M-H]− [M+H]+
239.0496 185.1073
239.0495 185.1070
-0.42 -1.62
Acetamiprid Acibenzolar-S-methyl Aclonifen Alachlor Albendazole Aldicarb Aldicarb sulfone Aldicarb sulfoxide Allethrin isomer 1 Allethrin isomer 2 Ametryne Aminocarb Amitraz Amitrol Ampa Anilazine Anilofos Asulam Atrazine Atrazine desethyl Atrazine desisopropyl Azaconazole Azamethiphos Azinphos ethyl Azinphos methyl Azobenzene Azocyclotin Azoxystrobin Barban Benalaxyl Bendiocarb Benfluralin Benfuracarb Bensulfuron methyl Bensulide Bentazone Benzidine
Food Anal. Methods Table 1 (continued) Compound
Elemental composition (M) tR (min) Ion
Theoretical m/z Experimental m/z Error (ppm)
Bifenazate Bifenox Bitertanol
C17H20N2O3 C14H9Cl2NO5 C20H23N3O2
5.99 6.74 5.99
C13H12NO+ C13H6Cl2NO4+ C18H21O2+
198.0913 309.9668 269.1536
198.0913 309.9668 269.1536
0.00 0.00 0.00
Boscalid
C18H12Cl2N2O C31H23BrO3 C31H23BrO3 C9H13BrN2O2 C30H23BrO4 C30H23BrO4 C8H8BrCl2O3PS C7H3ONBr2 C13H12BrCl2N3O C13H12BrCl2N3O C13H24N4O3S C16H23N3OS C17H26ClNO2 C7H14N2O2S C7H14N2O4S C14H21N3O4 C12H13ClN2O C10H23O2PS2
5.85 7.54 7.67 4.42 6.76 6.82 7.12 5.07 5.66 5.84 5.30 6.08 7.18 4.17 2.56 7.37 5.42 6.48
[M+H]+ [M-H]− [M-H]− C5H6BrN2O2+ [M-H]− [M-H]− [M+H]+ [M-H]− [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+Na]+ [M+Na]+ C10H14N3O4+ [M+H]+ C2H8O2PS2+
343.0399 521.0758 521.0758 204.9607 525.0707 525.0707 364.8565 273.8509 375.9614 375.9614 317.1642 306.1635 312.1725 213.0668 245.0564 240.0979 237.0789 158.9698
343.0397 521.0760 521.0760 204.9610 525.0723 525.0721 364.8574 273.8512 375.9612 375.9611 317.1646 306.1632 312.1729 213.0668 245.0569 240.0980 237.0782 158.9696
-0.58 0.38 0.38 1.46 3.04 2.67 2.47 1.10 -0.53 -0.80 1.26 -0.98 1.28 0.00 2.56 0.42 -0.84 -1.26
C12H11NO2 C9H9N3O2 C12H15NO3 C12H15NO4 C20H32N2O3S C12H13NO2S C15H14Cl2F3N3O3 C9H10BrClN2O2 C10H13ClN2 C12H14Cl3O4P C20H9Cl3F5N3O3 C10H8ClN3O C5H13NCl+ C10H12ClNO2 C10H13ClN2O C15H15ClN2O2 C9H11Cl3NO3PS C7H7Cl3NO3PS C12H12ClN5O4S
4.95 2.24 4.81 3.75 8.11 5.05 6.35 5.74 3.35 6.21 7.33 3.78 0.28 5.93 4.89 5.67 7.22 6.71 4.92
C10H9O+ [M+H]+ [M+H]+ C10H11O2+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M]+ C7H7ClNO2+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+
145.0648 192.0768 222.1125 163.0754 381.2206 236.0740 412.0437 292.9687 197.0840 358.9768 539.9702 222.0429 122.0370 172.0160 213.0789 291.0895 349.9336 321.9023 358.0371
145.0648 192.0768 222.1124 163.0755 381.2200 236.0744 412.0439 292.9688 197.0841 358.9769 539.9703 222.0428 122.0370 172.0158 213.0787 291.0898 349.9345 321.9029 358.0373
0.00 0.00 -0.45 0.61 -1.57 1.69 0.49 0.34 0.51 0.28 0.19 -0.45 4.22 -1.16 -0.94 1.03 2.57 1.86 0.56
C15H19N5O7S C17H26ClNO3S C17H26ClNO3S C17H26ClNO4S C14H23NO2S C17H13ClFNO4 C14H8Cl2N4 C12H14ClNO2 C6H3Cl2NO2
4.79 7.02 5.70 5.03 5.01 6.46 6.60 5.39 1.18
[M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ C7H5ClN+ [M+H]+ C5H2Cl2N+
414.1078 360.1395 360.1395 376.1344 270.1522 350.0590 138.0105 240.0786 145.9559
414.1085 360.1401 360.1402 376.1343 270.1512 350.0574 138.0104 240.0788 145.9555
1.69 1.67 1.04 -0.27 -3.70 -4.57 -0.72 0.83 -2.74
Brodifacoum isomer 1 Brodifacoum isomer 2 Bromacil Bromadiolone isomer 1 Bromadiolone isomer 2 Bromophos methyl Bromoxynil Bromuconazole isomer 1 Bromuconazole isomer 2 Bupirimate Buprofezin Butachlor Butocarboxim Butoxycarboxim Butralin Buturon Cadusafos Carbaryl Carbendazim Carbofuran Carbofuran 3-hydroxy Carbosulfan Carboxine Carfentazone ethyl Chlorbromuron Chlordimeform Chlorfenvinfos Chlorfluazuron Chloridazon Chlormequat chloride Chloropropham Chlorotoluron Chloroxuron Chlorpyrifos Chlorpyrifos methyl Chlorsulfuron Cinosulfuron Clethodim isomer E Clethodim isomer Z Clethodim sulfoxide Clethodim imine Clodinafop-propargyl Clofentezine Clomazone Clopyralid
Food Anal. Methods Table 1 (continued) Compound
Elemental composition (M) tR (min) Ion
Theoretical m/z Experimental m/z Error (ppm)
Clothianidin Coumaphos Cyanazine
C6H8ClN5O2S C14H16ClO5PS C9H13ClN6
3.72 6.60 4.61
C6H9N4S+ [M+H]+ [M+H]+
169.0541 363.0217 241.0963
169.0542 363.0219 241.0966
-0.59 0.55 1.24
Cyazofamid
C13H13ClN4O2S C11H21NOS C15H23NO4 C17H27NO3S C7H10N4O3 C24H25NO3 C15H18ClN3O C14H15N3 C6H10N6 C6H12O3N2 C5H10N2S2 C12H17NO C6H15O3PS2 C7H12ClN5 C16H16N2O4 C8H15N5S C23H32N2OS C12H21N2O3PS
6.35 6.71 4.22 6.87 1.63 7.76 5.54 5.18 0.46 0.40 2.51 5.01 4.59 4.58 5.65 3.99 7.54 6.57
C2H6NO2S+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+Na]+ [M+H]+ [M+H]+ [M+H]+ C6H11O2N2+ C3H6NS2+ [M+H]+ [M+Na]+ C3H5ClN5+ C9H12NO3+ [M+H]+ [M+H]+ [M+H]+
108.0114 216.1417 282.1700 326.1784 199.0826 398.1727 292.1211 226.1339 167.1040 143.0815 119.9936 192.1383 253.0092 146.0227 182.0812 214.1121 385.2308 305.1083
108.0115 216.1417 282.1701 326.1785 199.0823 398.1724 292.1210 226.1336 167.1041 143.0818 119.9937 192.1381 253.0099 146.0223 182.0816 214.1119 385.2309 305.1084
0.96 0.00 0.35 0.31 -1.51 -0.75 -0.34 -1.33 0.60 2.10 0.87 -1.04 2.77 -2.74 2.20 -0.93 0.26 0.33
C4H7Br2Cl2O4P C8Cl2H6O3 C10H13Cl2O3PS C9H11Cl2FN2O2S2 C9H8Cl2O3 C4H7Cl2O4P C6H4N2O2Cl2 C8H16NO5P C4H11NO2 C14H21NO4 C31H24O3 C31H24O3 C19H17Cl2N3O3 C16H18N2O3 C17H17N2 C14H9ClF2N2O2 C19H11F5N2O2 C11H21N5S C12H18ClNO2S
5.31 4.49 7.20 6.34 5.42 4.56 5.40 3.39 0.27 5.65 7.15 7.29 6.32 5.14 4.11 6.00 6.74 5.06 5.67
C2H8O4P+ C7H6Cl2O− C6H6Cl2O3PS+ C7H5Cl2FNS+ C6H3Cl2O [M+H]+ [M-H]− C6H10NO+ C4H10NO+ C11H16NO4+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M]+ [M-H]− [M+H]+ [M+H]+ C11H15ClNOS+
127.0155 174.9723 258.9147 223.9498 160.9566 220.9532 204.9577 112.0757 88.0757 226.1074 445.1798 445.1798 406.0720 287.1390 249.1392 309.0248 395.0813 256.1590 244.0557
127.0148 174.9730 258.9154 223.9499 160.9567 220.9531 204.9585 112.0757 106.0864 226.1074 445.1798 445.1796 406.0722 287.1389 249.1390 309.0252 395.0811 256.1595 244.0560
-5.51 4.00 2.70 0.45 0.62 -0.45 3.90 0.00 0.94 0.00 0.00 -0.45 0.49 -0.35 -0.80 1.29 -0.51 1.95 1.23
C5H12NO3PS2 C21H22ClNO4 C21H22ClNO4 C15H17Cl2N3O C12H11N C12H12Br2N2 C9H10Cl2N2O C9H14N2O2S C7H6N2O5
3.85 5.37 5.45 6.12 6.09 0.26 5.08 5.03 5.31
C2H6O2PS+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M-Br2-H]+ [M+H]+ C7H9N+ [M-H]−
124.9821 388.1310 388.1310 326.0821 170.0964 183.0917 233.0243 106.0651 197.0204
124.9819 388.1313 388.1311 326.0823 170.0965 183.0916 233.0245 106.0650 197.0203
-1.60 0.77 0.26 0.61 0.59 -0.55 0.86 -0.94 0.00
Cycloate Cycloheximid Cycloxydim Cymoxanil Cyphenothrin Cyproconazole Cyprodinil Cyromazine Daminozide Dazomet DEET Demeton-S-methyl Desethyl terbuthylazine Desmedipham Desmetryn Diafenthiuron Diazinon Dibrom Dicamba Dichlofenthion Dichlofluanid Dichlorprop Dichlorvos Dicloran Dicrotophos Diethanolamine Diethofencarb Difenacoum isomer 1 Difenacoum isomer 2 Difenoconazole Difenoxuron Difenzoquat Diflubenzuron Diflufenican Dimethametryn Dimethenamid Dimethoate Dimethomorph isomer 1 Dimethomorph isomer 2 Diniconazole Diphenylamine Diquat dibromide Diuron DMST DNOC
Food Anal. Methods Table 1 (continued) Compound
Elemental composition (M) tR (min) Ion
Theoretical m/z Experimental m/z Error (ppm)
Edifenphos Emamectin isomer 1 Emamectin isomer 2
C14H15O2PS2 C49H75NO13 C49H75NO13
6.21 5.74 5.81
[M+H]+ [M+H]+ [M+H]+
311.0324 886.5311 886.5311
311.0325 886.5342 886.5343
0.32 0.32 0.33
Endosulfan sulfate
C9H6Cl6O4S C14H14NO4PS C17H13ClFN3O C9H19NOS C14H15Cl2N3O2 C2H6ClO3P C7H12N4O3S2 C11H15NO2S C11H15NO4S C11H15NO3S C9H22O4P2S4 C13H9Cl2F3N4OS C13H18O5S C8H19O2PS2 C14H19NO C3H6N2S C25H28O3 C21H23F2NO2
6.65 6.82 5.79 6.26 5.74 1.40 3.80 5.06 3.71 3.48 7.26 5.57 5.97 5.83 4.62 0.41 7.96 7.34
[M-H]− [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M-H]− C5H10N3O2S2+ C7H7O+ C7H7O+ C7H7O+ C5H12O2PS2+ [M+H]+ C11H12O4S+ [M+Na]+ [M+H]+ [M+H]+ [M+NH4]+ [M+H]+
418.8045 324.0454 330.0804 190.1260 328.0614 142.9670 208.0209 107.0491 107.0491 107.0491 199.0011 396.9899 241.0529 243.0637 218.1539 103.0324 394.2377 360.1770
418.8066 324.0458 330.0801 190.1260 328.0614 142.9672 208.0210 107.0494 107.0492 107.0493 199.0015 396.9901 241.0525 243.0637 218.1541 103.0329 394.2372 360.1767
5.01 1.23 -0.91 0.00 0.00 0.41 0.48 2.80 0.93 1.81 2.01 0.50 -1.66 0.00 0.92 4.85 -1.27 -0.83
C10H17N2O4PS C22H18N2O4 C10H16NO5PS2 C17H17N3OS C13H22NO3PS C13H22NO5PS C13H22NO4PS C17H12Cl2N2O C20H22N2O C15H13N3O2S C14H17Cl2NO2 C9H12NO5PS C12H17NO2 C18H16ClNO5 C17H19NO4 C11H6Cl2N2 C22H23NO3 C19H31N C20H33NO
6.52 6.51 5.64 5.79 5.70 4.73 4.31 5.66 7.14 4.94 5.84 6.10 5.55 6.83 6.10 5.55 7.56 4.88 4.91
[M+H]+ C21H19N2O2+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ C6H7O+ [M+H]+ [M+H]+ [M+H]+ C8H13O+ [M+H]+ [M+H]+
293.0719 331.1441 326.0280 312.1165 304.1131 336.1029 320.1080 331.0399 307.1805 300.0801 302.0709 278.0247 95.0491 362.0790 302.1387 236.9981 125.0960 274.2529 304.2635
293.0715 331.1438 326.0278 312.1165 304.1129 336.1029 320.1078 331.0402 307.1807 300.0803 302.0705 278.0246 95.0491 362.0790 302.1389 236.9982 125.0954 274.2533 304.2639
-1.36 -2.72 -0.61 0.00 -0.66 0.00 -0.62 0.91 0.65 0.67 -1.32 -0.36 0.00 0.00 0.66 0.42 -4.80 1.46 1.31
C24H27N3O4 C11H17O4PS2 C10H15O3PS2 C18H15SnCl C9H12N2O C12H4Cl2F6N4OS C15H12F3NO4 C19H20F3NO4 C13H4Cl2F6N4O4
7.31 5.18 6.48 4.69 3.63 6.33 5.61 7.17 7.04
[M+H]+ [M+H]+ [M+H]+ [M-Cl]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+
422.2074 309.0379 279.0273 351.0196 165.1022 436.9460 328.0791 384.1417 464.9587
422.2084 309.0378 279.0274 351.0192 165.1022 436.9459 328.0791 384.1414 464.9584
2.37 -0.32 0.36 -1.14 0.00 -0.23 0.00 -0.78 -0.65
EPN Epoxiconazole EPTC Etaconazol Ethephon Ethidimuron Ethiofencarb Ethiofencarb sulfone Ethiofencarb sulfoxide Ethion Ethiprole Ethofumesate Ethoprophos Ethoxyquin Ethylenthiourea Etofenprox Etoxazole Etrimphos Famoxadone Famphur Fenamidone Fenamiphos Fenamiphos sulfone Fenamiphos sulfoxide Fenarimol Fenazaquin Fenbendazole Fenhexamid Fenitrothion Fenobucarb Fenoxaprop-P-ethyl Fenoxycarb Fenpiclonil Fenpropathrin Fenpropidine Fenpropimorph Fenpyroximate Fensulfothion Fenthion Fentin chloride Fenuron Fipronil Fluazifop Fluazifop-butyl Fluazinam
Food Anal. Methods Table 1 (continued) Compound
Elemental composition (M) tR (min) Ion
Theoretical m/z Experimental m/z Error (ppm)
Fluchloralin Flucythrinate Fludioxonil
C12H13ClF3N3O4 C26H23F2NO4 C12H6F2N2O2
6.91 7.45 5.66
[M+H]+ [M+NH4]+ [M-H]−
356.0619 469.1933 247.0325
356.0620 469.1931 247.0337
0.28 -0.43 4.85
Flufenacet
C14H13F4N3O2S C21H11ClF6N2O3 C10H11F3N2O C16H8Cl2FN5O C7H5Cl2FN2O3 C16H15F2N3Si C17H16F3NO2 C16H13F2N3O C15H10ClF3N2O6S C10H15OPS2 C17H20N6O7S C12H10ClN3O C11H15N3O2 C2H7O3P C9H18NO3PS2 C11H8N2O C17H19NO4 C18H26N2O5S
6.15 7.17 4.96 5.89 4.54 5.93 6.09 4.96 6.00 6.58 4.57 4.98 1.16 0.36 4.98 3.14 5.59 7.07
C11H13FNO+ [M+H]+ [M+H]+ [M+H]+ C5Cl2H2FN2O− [M+H]+ [M+H]+ [M+H]+ [M+NH4]+ C2H6OPS+ [M+H]+ [M+H]+ [M+H]+ H4PO3+ C5H11NO3PS2+ [M+H]+ [M+H]+ [M+H]+
194.0976 489.0435 233.0896 376.0163 194.9534 316.1076 324.1206 302.1099 456.0238 108.9871 453.1187 248.0585 222.1237 82.9893 227.9912 185.0709 302.1387 383.1635
194.0971 489.0434 233.0897 376.0168 194.9534 316.1076 324.1208 302.1098 456.0233 108.9870 453.1184 248.0580 222.1235 82.9899 227.9917 185.0709 302.1394 383.1635
-1.03 -0.20 0.43 1.33 0.00 0.00 0.62 -0.33 -1.10 3.67 -0.66 -2.02 -0.90 7.23 2.19 0.00 2.32 0.00
C14H21NO3 C19H22O6 C5H12NO4P C7H14NO5P C3H8NO5P C17H17ClO6 C15H11ClF3NO4 C16H8Cl2F6N2O3 C12H20N4O2 C17H21ClN2O2S C25H24F6N4 C14H14Cl2N2O C9H10Cl2N2O C16H20N2O3 C15H19N3O4 C13H15N3O3 C17H17N3O3 C9H10ClN5O2 C22H17ClF3N3O7
6.21 3.70 0.32 0.41 0.33 5.15 6.04 6.63 4.32 7.24 6.02 4.52 3.69 4.11 3.82 3.41 4.56 3.81 6.79
[M+H]+ [M-H]− [M-H]− [M-H]− [M-H]− [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+
252.1594 345.1344 180.0431 222.0537 168.0067 353.0786 362.0401 460.9889 253.1659 353.1085 495.1978 297.0556 257.0243 289.1547 306.1448 262.1186 312.1343 256.0596 528.0780
252.1591 345.1353 180.0435 222.0539 168.0072 353.0784 362.0400 460.9885 253.1661 353.1086 495.1975 297.0556 257.0243 289.1547 306.1450 262.1187 312.1342 256.0594 528.0790
-1.19 2.61 2.22 0.90 2.98 -0.57 -0.28 -0.87 0.79 0.28 -0.61 0.00 0.00 0.00 0.65 0.38 -0.32 -0.78 1.89
C7H3I2NO C13H13N3Cl2O3 C18H28N2O3 C9H17ClN3O3PS C11H16NO4PS C15H24NO4PS C11H15NO2 C12H18O4S2 C12H18N2O
5.41 6.60 5.68 6.27 5.54 6.84 5.18 6.09 5.04
[M-H]− [M+H]+ C9H11+ [M+H]+ C8H8O4PS+ [M+H]+ C6H7O+ C6H5O3S2+ [M+H]+
369.8231 330.0407 119.0855 314.0490 230.9875 346.1236 95.0491 188.9675 207.1492
369.8228 330.0409 119.0855 314.0488 230.9883 346.1245 95.0488 188.9677 207.1495
-0.81 0.61 0.00 -0.64 3.46 2.60 -3.16 1.06 1.45
Flufenoxuron Fluomethuron Fluquinconazole Fluroxypyr Flusilazole Flutolanil Flutriafol Fomesafen Fonofos Foramsulfuron Forchlorfenuron Formetanate Fosetyl Fosthiazate Fuberidazol Furalaxyl Furathiocarb Furmecyclox Gibberellic acid Glufosinate ammonium Glufosinate-N-acetyl Glyphosate Griseofulvin Haloxyfop Hexaflumuron Hexazinone Hexythiazox Hydramethylnon Imazalil Imazalil metabolite Imazamethabenz-methyl Imazamox Imazapyr Imazaquin Imidacloprid Indoxacarb Ioxynil Iprodione Iprovalicarb Isazophos Isocarbophos Isofenphos Isoprocarb Isoprothiolane Isoproturon
Food Anal. Methods Table 1 (continued) Compound
Elemental composition (M) tR (min) Ion
Theoretical m/z Experimental m/z Error (ppm)
Isoxaben Isoxaflutole Ivermectin
C18H24N2O4 C15H12F3NO4S C48H72O14
5.96 5.78 7.58
[M+H]+ [M+H]+ [M+Na]+
333.1809 360.0512 895.4814
333.1798 360.0516 895.4811
-3.30 1.11 -0.34
Karbutilate
C14H21N3O3 C18H19NO4 C19H15ClF3NO7 C13H18N2O2 C9H10Cl2N2O2 C17H8Cl2F8N2O3 C10H19O7PS C10H19O6PS2 C4H4N2O2 C10H20NO5PS2 C10H11ClO3 C16H14N2O2S C14H13N3 C8H16NO3PS2 C7H16N+ C17H19NO2 C14H13NO7S C24H16F6N4O2
4.70 6.33 7.16 4.64 5.64 7.00 4.76 6.07 0.41 6.29 5.41 5.82 5.91 4.42 0.40 6.03 4.79 6.99
[M+H]+ C17H16NO3+ [M+Na]+ C7H9N2O2+ [M+H]+ [M+H]+ C4H3O3+ [M+H]+ [M+H]+ C6H14O3PS2+ C7H6ClO− C9H10NO+ [M+H]+ [M+H]+ [M]+ [M+H]+ [M+H]+ [M+H]+
280.1656 282.1125 484.0381 153.0659 249.0192 510.9857 99.0077 331.0433 113.0346 226.9961 141.0113 148.0757 224.1182 270.0382 114.1283 270.1489 340.0485 507.1250
280.1655 282.1116 484.0386 153.0662 249.0195 510.9870 99.0080 331.0435 113.0348 226.9961 141.0109 148.0757 224.1183 270.0385 114.1283 270.1492 340.0484 507.1252
-0.36 -3.19 1.03 1.96 1.20 2.54 3.03 0.60 1.77 0.00 -2.84 0.00 0.45 1.11 0.00 1.11 -0.29 0.39
C15H21NO4 C10H10N4O C14H16ClN3O C10H11N3OS C7H13O5PS C2H8NO2PS C6H11N2O4PS3 C11H15NO2S C11H15NO3S C5H10N2O2S C11H21N5OS C22H28N2O3 C9H11BrN2O2 C15H22ClNO2 C9H11NO2 C10H13ClN2O2 C8H14N4OS C14H15N5O6S C7H13O6P
5.07 3.61 5.30 4.81 5.64 0.55 5.63 5.56 3.64 2.86 4.38 5.98 5.22 6.08 4.57 4.33 4.62 4.80 4.06
[M+H]+ [M+H]+ C9H12N+ C8H9N2S+ C6H10O4PS+ CH5NO2P+ C3H5N2O+ C9H12OS+ C9H13O2S+ C3H4NS+ [M+H]+ C18H21N2O3+ [M+H]+ [M+H]+ C7H9O+ [M+H]+ [M+H]+ [M+H]+ C2H8O4P+
280.1543 203.0927 134.0964 165.0481 209.0032 94.0052 85.0396 169.0682 185.0631 88.0215 272.1540 149.0597 259.0077 284.1412 109.0648 229.0738 215.0961 382.0816 127.0155
280.1541 203.0925 134.0958 165.0482 209.0031 94.0054 85.0403 169.0678 185.0630 88.0217 272.1538 149.0596 259.0080 284.1415 109.0649 229.0739 215.0963 382.0816 127.0153
-0.71 -0.98 -4.47 0.61 -0.48 2.13 5.88 -2.37 -0.54 2.27 -0.73 -0.67 1.16 1.06 0.92 0.44 0.93 0.00 -1.57
C9H17NOS C7H14NO5P C9H11ClN2O2 C9H11ClON2 C4H9NO C15H17ClN4 C18H13NO3 C12H16Cl2N2O C5S2NH11
5.77 3.18 5.10 4.48 0.27 5.73 4.75 6.18 0.49
[M+H]+ C2H7O4P+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ C10H10N+ [M+H]+ C3H5S2+
188.1104 127.0155 215.0582 199.0633 88.0757 289.1215 144.0808 275.0715 104.9827
188.1106 127.0156 215.0577 199.0632 88.0762 289.1212 144.0812 275.0711 104.9830
1.06 0.79 -2.32 -0.50 5.68 -1.04 1.71 -1.45 2.86
Kresoxim methyl Lactofen Lenacil Linuron Lufenuron Malaoxon Malathion Maleic hydrazine Mecarbam Mecoprop Mefenacet Mepanipyrim Mephosfolam Mepiquat chloride Mepronil Mesotrione Metaflumizone Metalaxyl Metamitron Metazachlor Methabenzthiazuron Methacrifos Methamidophos Methidathion Methiocarb Methiocarb sulfoxide Methomyl Methoprotryne Methoxyfenozide Metobromuron Metolachlor Metolcarb Metoxuron Metribuzin Metsulfuron methyl Mevinphos Molinate Monocrotophos Monolinuron Monuron Morpholin Myclobutanil Naptalam Neburon Nereistoxin
Food Anal. Methods Table 1 (continued) Compound
Elemental composition (M) tR (min) Ion
Theoretical m/z Experimental m/z Error (ppm)
Nitenpyram C11H15ClN4O2 N,N-Diethyl-2-naphtoloxypropamide C17H21O2N Norflurazone C12H9ClF3N3O
2.95 5.91 5.20
[M+H]+ [M+H]+ [M+H]+
271.0956 272.1645 304.0459
271.0961 272.1646 304.0457
1.84 0.37 -0.66
Novaluron
C17H9ClF8N2O4 C17H12ClFN2O C14H16ClNO3 C5H12NO4PS C12H16ClNOS C12H18N4O6S C15H18Cl2N2O3 C14H18N2O4 C7H13N3O3S C15H13N3O3S C15H11ClF3NO4 C15H20ClN3O C8H10NO6P C12H14Cl2N2 C10H14NO5PS C8H10NO5PS C10H21NOS C13H15Cl2N3
6.81 5.32 5.10 1.10 6.56 6.10 7.21 4.55 2.82 3.97 7.07 5.46 4.60 0.27 6.45 5.88 6.69 5.97
[M-H]− [M+H]+ [M+H]+ C2H6O2PS+ C7H6Cl+ [M+H]+ [M+H]+ C12H15N2O2+ C3H6NO+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M-Cl2-H]+ C6H7NO5PS+ [M+H]+ [M+H]+ [M+H]+
491.0050 315.0695 282.0891 124.9821 125.0153 345.0874 345.0757 219.1128 72.0444 316.0751 362.0401 294.1368 248.0319 185.1073 235.9777 264.0090 204.1417 284.0716
491.0061 315.0692 282.0890 124.9822 125.0154 345.0882 345.0772 219.1131 72.0447 316.0751 362.0398 294.1370 248.0315 185.1069 235.9780 264.0092 204.1417 284.0716
2.24 -0.95 -0.35 0.80 0.80 2.32 4.35 1.37 4.16 0.00 -0.83 0.68 -1.61 -2.16 1.27 0.76 0.00 0.00
C19H21ClN2O C13H19N3O4 C16H16N2O4 C23H26O3 C12H17O4PS2 C12H15ClNO4PS2 C11H12NO4PS2 C10H19ClNO5P H3O3P C6H3Cl3N2O2 C19H12F4N2O2 C19H30O5 C14H28NO3PS2 C11H18N4O2 C11H20N3O3PS C17H26ClNO2 C17H26ClNO2 C15H16Cl3N3O2 C13H11Cl2NO2
6.65 7.23 5.61 7.96 6.51 6.73 4.30 4.36 0.50 3.25 6.96 7.03 6.76 3.51 6.41 6.81 6.73 5.40 6.09
[M+H]+ C8H10N3O4+ C8H10NO3+ [M+H]+ C10H11O2+ C8H5ClNO2+ C9H6NO2+ [M+H]+ [M-H]− [M+H]+ [M+H]+ C11H13O2+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ C12H13Cl3NO2+ [M+H]+
329.1415 212.0666 168.0655 351.1955 163.0754 182.0003 160.0393 300.0762 80.9747 240.9333 377.0908 177.0910 354.1321 239.1503 306.1036 312.1725 312.1725 308.0006 284.0240
329.1415 212.0667 168.0661 351.1956 163.0758 182.0005 160.0394 300.0762 80.9750 240.9334 377.0910 177.0913 354.1324 239.1503 306.1034 312.1723 312.1723 308.0008 284.0242
0.00 0.47 3.57 0.28 2.45 1.10 0.62 0.00 3.70 2.49 0.53 1.69 0.85 0.00 -0.65 -0.64 -0.64 0.65 0.70
C11H15BrClO3PS C10H12O5 C12H17NO2 C10H19N5O C10H19N5S C11H14ClNO C9H20N2O2 C9H9Cl2NO C22H22ClN3O5
6.79 4.09 5.69 4.05 4.76 5.27 1.14 5.47 6.93
[M+H]+ [M-H]− C10H15O+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+
372.9424 211.0612 151.1117 226.1662 242.1434 212.0837 189.1598 218.0134 444.1321
372.9424 211.0613 151.1118 226.1659 242.1437 212.0836 189.1599 218.0132 444.1321
0.00 0.47 0.66 -1.33 1.24 -0.47 0.53 -0.92 0.00
Nuarimol Ofurace Omethoate Orbencarb Oryzalin Oxadiazon Oxadixyl Oxamyl Oxfendazole Oxyfluorfen Paclobutrazol Paraoxon methyl Paraquat dichloride Parathion Parathion-methyl Pebulate Penconazole Pencycuron Pendimethalin Phenmedipham Phenothrin Phenthoate Phosalone Phosmet Phosphamidon Phosphonic acid Picloram Picolinafen Piperonyl butoxide Piperophos Pirimicarb Pirimiphos methyl Pretilachlor isomer 1 Pretilachlor isomer 2 Prochloraz Procymidone Profenofos Prohexadione Promecarb Prometon Prometryn Propachlor Propamocarb Propanil Propaquizafop
Food Anal. Methods Table 1 (continued) Compound
Elemental composition (M) tR (min) Ion
Theoretical m/z Experimental m/z Error (ppm)
Propargite Propazine Propetamphos
C19H26O4S C9H16ClN5 C10H20NO4PS
7.40 5.41 6.16
[M+Na]+ [M+H]+ C3H11NO2PS+
373.1444 230.1167 156.0243
373.1446 230.1169 156.0245
0.54 0.87 1.28
Propham
C10H13NO2 C15H17Cl2N3O2 C15H22ClNO2 C11H15NO3 C4H8N2S C12H11Cl2NO C14H17IN2O2 C14H21NOS C15H16F3N5O4S C10H11N5O C13H15NO2 C19H18ClN3O4 C20H18O4 C14H20N3O5PS C19H25ClN2OS C14H17N2O4PS C14H12Cl2N2O C14H12Cl2N2O
5.30 6.13 6.40 4.75 0.53 5.89 7.51 6.91 5.64 0.70 4.89 6.60 6.47 6.51 7.61 5.86 4.57 4.65
C7H8NO2+ [M+H]+ C10H15N+ [M+H]+ [M+H]+ C7H6Cl2NO+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M + H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+
138.0550 342.0771 148.1121 232.0944 117.0481 189.9821 373.0407 252.1417 420.0948 218.1036 218.1176 388.1059 323.1278 374.0934 365.1449 341.0719 295.0399 295.0399
138.0560 342.0771 148.1122 232.0944 117.0481 189.9824 373.0405 252.1418 420.0946 218.1036 218.1176 388.1056 323.1277 374.0935 365.1451 341.0719 295.0390 295.0397
7.24 0.00 0.68 0.00 0.00 1.58 -0.54 0.40 -0.48 0.00 0.00 -0.77 -0.31 0.27 0.55 0.00 -3.05 -0.68
C12H13N3 C20H19NO3 C11H11NO C12H15N2O3PS C11H8ClNO2 C10H6ClNO2 C15H8Cl2FNO C19H17ClN2O4 C22H26O3 C14H17N5O7S2 C23H22O6 C10H19N5O C17H29NO3S C14H20N2O C7H12ClN5 C41H65NO10 C42H67NO10 C23H30O4 C21H27NO5
4.54 7.10 4.28 6.35 3.67 4.59 6.75 6.85 7.73 4.96 6.15 4.05 7.13 5.51 4.44 5.37 5.54 7.62 5.60
[M+H]+ [M+H]+ [M+H]+ [M+H]+ C11H7ClNO+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ C17H22O3+ [M+H]+
200.1182 322.1438 174.0913 299.0614 204.0211 208.0160 308.0040 373.0950 339.1955 432.0642 395.1489 226.1662 328.1941 233.1648 202.0854 732.4681 746.4838 273.1485 374.1962
200.1179 322.1440 174.0912 299.0615 204.0212 208.0159 308.0043 373.0949 339.1948 432.0631 395.1487 226.1663 328.1942 233.1648 202.0856 732.4677 746.4832 273.1490 374.1961
-1.50 0.62 -0.57 0.33 0.44 -0.48 0.97 -0.27 -2.06 -2.55 -0.51 0.44 0.30 0.00 0.99 -0.55 -0.80 -1.83 -0.27
C18H35NO2 C14H13ClO5S C15H16N4O5S C8H20O5P2S2 C12H19O2PS3 C16H22ClN3O C18H24ClN3O C15H23NO C9H16N4OS
4.91 4.86 4.87 6.65 7.31 5.86 6.85 6.05 4.27
[M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+
298.2741 329.0245 365.0914 323.0300 323.0358 308.1524 334.1681 234.1852 229.1118
298.2740 329.0245 365.0913 323.0299 323.0358 308.1522 334.1683 234.1854 229.1120
-0.34 0.00 -0.27 -0.31 0.00 -0.65 0.60 0.85 0.87
Propiconazole Propisochlor Propoxur Propylene thiourea Propyzamid Proquinazid Prosulfocarb Prosulfuron Pymetrozin Pyracarbolid Pyraclostrobin Pyranocoumarin Pyrazophos Pyridaben Pyridaphenthion Pyrifenox isomer 1 Pyrifenox isomer 2 Pyrimethanil Pyriproxifen Pyroquilon Quinalphos Quinmerac Quinoclamine Quinoxyfen Quizalofop-P-ethyl Resmethrin (R+S isomers) Rimsulfuron Rotenone Secbumeton Sethoxydim Siduron Simazine Spinosyn A Spinosyn D Spiromesifen Spirotetramat Spiroxamine Sulcotrione Sulfometuron methyl Sulfotep Sulprofos Tebuconazole Tebufenpyrad Tebutam Tebuthiuron
Food Anal. Methods Table 1 (continued) Compound
Elemental composition (M) tR (min) Ion
Theoretical m/z Experimental m/z Error (ppm)
Teflubenzuron Tembotrione Temephos
C14H6Cl2F4N2O2 C17H16ClF3O6S C16H20O6P2S3
6.68 5.76 7.18
[M-H]− C15H14ClO5S+ [M+H]+
378.9670 341.0245 466.9970
378.9673 341.0250 466.9971
0.79 1.47 0.21
Tepraloxydim isomer 1
C17H24ClNO4 C17H24ClNO4 C9H13ClN2O2 C9H21O2PS3 C10H19N5O C9H16ClN5 C10H19N5S C10H9Cl4O4P C10H7N3S C10H9ClN4S C8H10ClN5O3S C9H8N4OS C12H13N5O6S2 C5H11NS3 C10H18N4O4S3 C9H18N2O2S C12H14N4O4S2 C9H11Cl2O3PS
5.84 4.65 4.50 7.13 4.10 5.54 4.79 6.08 2.98 4.30 3.43 4.50 4.68 0.78 4.77 4.99 4.72 6.67
[M+H]+ [M+H]+ [M-H]− C4H13O2PS2+ [M+H]+ [M+H]+ [M+H]+ C8H3Cl4+ [M+H]+ [M+H]+ C8H11N4OS+ [M+H]+ [M+H]+ C5H5S3+ [M+Na]+ [M+Na]+ [M+H]+ [M+H]+
342.1467 342.1467 215.0593 187.0011 226.1662 230.1167 242.1434 127.0155 202.0433 253.0309 211.0648 221.0492 388.0380 136.9548 377.0382 241.0981 343.0529 300.9616
342.1467 342.1462 215.0585 187.0017 226.1662 230.1171 242.1435 127.0154 202.0437 253.0309 211.0647 221.0488 388.0375 136.9551 377.0379 241.0983 343.0528 300.9615
0.00 -1.46 -3.72 3.21 0.00 1.30 0.41 -0.79 1.98 0.00 -1.03 -1.81 -1.29 2.19 -0.80 0.83 -0.29 -0.33
C20H27NO3 C15H12Cl2F4O2 C14H16ClN3O2 C14H18ClN3O2 C14H18ClN3O2 C10H16Cl3NOS C14H16ClN5O5S C12H16N3O3PS C10H6ClN5O C4H8Cl3O4P C19H39NO C9H16ClN5 C6H15NO3 C20H19F3N2O4 C14H13F3N5O6S C15H15ClF3N3O C15H10ClF3N2O3 C13H16F3N3O4 C10H14Cl6N4O2
7.24 7.36 5.80 5.43 5.53 7.41 4.91 6.11 4.14 3.52 5.44 5.95 0.28 6.81 5.12 5.88 6.38 7.27 5.16
[M+H]+ C7H3F4+ [M+H]+ C2H4N3+ C2H4N3+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ C12H12ClF3NO+ [M-H]− [M+H]+ C9H12Cl6N3O+
330.2064 163.0165 294.1004 70.0399 70.0399 304.0091 402.0633 314.0723 248.0334 256.9299 298.3105 230.1167 150.1125 409.1370 438.0690 278.0554 357.0259 336.1166 387.9106
330.2064 163.0166 294.1007 70.0400 70.0400 304.0092 402.0630 314.0726 248.0333 256.9302 298.3105 230.1170 150.1120 409.1368 438.0685 278.0555 357.0265 336.1176 387.9102
0.00 0.61 1.02 1.43 1.43 0.33 -0.75 0.96 -0.40 1.17 0.00 1.30 -3.33 -0.49 -1.14 0.36 1.68 2.98 -1.03
C3H8S C13H16O5 C17H20ClN3O C8H18NO4PS2 C12H9Cl2NO3 C14H16Cl3NO2
0.26 5.35 5.53 3.65 6.27 6.51
[M+H]+ [M+H]+ [M+H]+ C6H12NOS + C11H10Cl2NO+ [M+H]+
77.0425 253.1071 318.1368 146.0634 242.0134 336.0319
77.0423 253.1072 318.1366 146.0637 242.0128 336.0316
-2.60 0.40 -0.63 2.05 -2.48 -0.89
C12H15N3O4S C12H15N3O3S
3.97 3.51
[M+H]+ [M+H]+
298.0856 282.0907
298.0863 282.0911
2.95 1.42
Tepraloxydim isomer 2 Terbacil Terbufos Terbumeton Terbuthylazine Terbutryn Tetrachovinphos Thiabendazole Thiacloprid Thiamethoxam Thidiazuron Thifensulfuron methyl Thiocyclam Thiodicarb Thiofanox Thiophanate methyl Tolclofos methyl Tralkoxidym Transfluthrin Triadimefon Triadimenol isomer 1 Triadimenol isomer 2 Triallat Triasulfuron Triazophos Triazoxide Trichlorfon Tridemorph Trietazine Triethanolamine Trifloxystrobin Trifloxysulfuron Triflumizole Triflumuron Trifluralin Triforine Trimethylsulfonium Trinexapac-ethyl Triticonazole Vamidothion Vinclozolin Zoxamide Veterinary drugs Albendazole sulfone Albendazole sulfoxide
Food Anal. Methods Table 1 (continued) Compound
Elemental composition (M) tR (min) Ion
Theoretical m/z Experimental m/z Error (ppm)
Amoxicillin Ampicillin Antimycin A
C16H19N3O5S C16H19N3O4S C28H40N2O9
0.93 3.17 7.59
C16H17N2O5S + [M+H]+ [M+H]+
349.0853 350.1169 549.2807
349.0857 350.1164 549.2804
1.15 -1.43 -0.55
Benzothiazole
C7H5NS C19H23N3O C8H10N4O2 C11H10N4O4 C15H12N2O C11H12O5N2Cl2 C22H23ClN2O8 C22H23ClN2O8 C17H18FN3O3 C38H69NO13 C12H18Cl2N2O C10H11O3Cl C19H18ClN3O5S C10H12N2O C19H20FN3O3 C21H21ClN2O8 C21H21ClN2O8 C14H11Cl2NO2
4.35 4.47 3.04 3.40 4.65 4.14 3.62 3.87 3.46 4.67 3.61 5.24 5.17 0.41 3.48 3.46 3.64 5.89
[M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M-H]− [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ C6H4ClO− [M+CH4OH]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ C13H8Cl2N−
136.0215 310.1914 195.0877 263.0775 237.1022 321.0051 479.1216 479.1216 332.1405 748.4842 277.0869 126.9951 468.0991 177.1022 358.1561 465.1059 465.1059 250.0196
136.0213 310.1914 195.0875 263.0775 237.1020 321.0052 479.1210 479.1206 332.1401 748.4823 277.0870 126.9951 468.0995 177.1022 358.1563 46.1041 465.1069 250.0210
-1.47 0.00 -1.03 0.00 -0.84 0.31 -1.25 -2.09 -1.20 -2.54 0.36 0.00 0.85 0.00 0.56 -3.87 2.15 5.60
C19H17N3Cl2O5S C19H17N3Cl2O5S C21H19F2N3O3 C41H64O14 C5H7N3O2 C17H21NO C50H74O14 C22H24N2O8 C15H17FN4O3 C19H22FN3O3 C50H75NO14 C49H73NO14 C37H67NO13 C18H22O2 C16H18N4O2S C18H20N4O4S C17H18F3N3O3 C14H10F3NO2 C14H12FNO3
5.34 5.45 3.72 4.45 1.29 4.30 7.99 3.98 3.33 3.54 7.14 7.14 4.32 5.47 4.16 4.29 3.31 6.22 4.75
[M+CH4OH]+ [M+CH4OH]+ [M+H]+ C35H55O11+ [M+H]+ C13H11+ C21H31O3+ [M+H]+ [M+H]+ [M+H]+ [M+Na]+ [M+Na]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ C14H9F3NO + [M+H]+
502.0601 502.0601 400.1467 651.3739 142.0611 167.0855 331.2268 445.1605 321.1357 360.1718 936.5080 922.4923 734.4685 271.1693 331.1223 389.1278 370.1373 264.0631 262.0874
502.0606 502.0609 400.1466 651.3733 142.0611 167.0856 331.2272 445.1608 321.1357 360.1720 936.5093 922.4902 734.4671 271.1693 331.1231 389.1271 370.1378 264.0628 262.0871
1.00 1.59 -0.25 -0.92 0.00 0.60 1.21 0.67 0.00 0.56 1.39 -2.28 -1.91 0.00 2.72 -1.80 0.14 -1.14 -1.14
C17H18F3NO C12H11ClN2O2S C15H22O3 C7H8ClN3O4S2 C8H8F3N3O4S2 C13H18O2 C19H16ClNO4 C12H7Cl3O2 C42H69NO15
4.75 4.70 6.33 2.64 3.58 5.97 5.90 6.69 4.93
[M+H]+ [M-H]− C7H13O2+ [M-H]− C8H6F3N2O4S2+ C12H17+ [M+H]+ C6H3Cl2O + [M+H]+
310.1413 329.0040 129.0910 295.9572 314.9716 161.1325 358.0841 160.9555 828.4740
310.1416 329.0033 129.0912 295.9568 314.9720 161.1325 358.0838 160.9559 828.4739
0.97 -2.13 1.55 -1.69 1.27 0.00 -0.84 2.49 -0.12
Benzydamine Caffeine Carbadox Carbamazepine Chloramphenicol Chlortetracycline iso. 1 Chlortetracycline iso. 2 Ciprofloxacin Clarithromycin Clenbuterol Clofibric acid Cloxacillin Cotinine Danofloxacin Demeclocycline isomer 1 Demeclocycline isomer 2 Diclofenac Dicloxacillin isomer 1 Dicloxacillin isomer 2 Difloxacin Digoxin Dimetridazole Diphenhydramine Doramectin Doxicycline Enoxacin Enrofloxacin Eprinomectin B1a Eprinomectin B1b Erythromycin Estrone Febantel 1 Febantel 2 Fleroxacin Flufenamic acid Flumequine Fluoxetine Furosemide Gemfibrozil Hydrochlorothiazide Hydroflumethiazide Ibuprofen Indomethacine Irgasan Josamycin
Food Anal. Methods Table 1 (continued) Compound
Elemental composition (M) tR (min) Ion
Theoretical m/z Experimental m/z Error (ppm)
Ketoprofen Leucomalachite green Levamisole
C16H14O3 C23H26N2 C11H12N2S
5.24 4.88 1.98
[M+H]+ [M+H]+ [M+H]+
255.1016 331.2169 205.0794
255.1008 331.2171 205.0790
-3.14 0.60 -1.95
Lincomycin
C18H34N2O6S C17H19F2N3O3 C23H24N2 C17H19FN4O4 C16H13N3O3 C14H11Cl2NO2 C15H15NO2 C11H10O5S C4H11N5 C6H9N3O3 C18H14Cl4N2O C23H27N3O7 C36H62O11 C14H14O3 C33H47NO13 C10H14N2 C12H9N3O5 C16H18FN3O3
2.94 3.47 5.06 3.30 4.42 6.26 6.25 3.16 0.27 1.06 5.35 3.06 8.94 5.27 4.37 0.40 4.20 3.38
[M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ C14H10Cl2NO + C15H14NO + [M-H]− [M+H]+ C4H6N3O2+ [M+H]+ [M+H]+ [M+Na]+ C13H13O + [M+H]+ [M+H]+ [M+H]+ [M+H]+
407.2210 352.1467 329.2012 363.1463 296.1030 278.0134 224.1070 253.0171 130.1087 128.0456 414.9933 458.1922 693.4184 185.0961 666.3120 163.1230 276.0615 320.1405
407.2206 352.1462 329.2013 363.1466 296.1025 278.0138 224.1071 253.0171 130.1086 128.0455 414.9934 458.1921 693.4207 185.0960 666.3115 163.1231 276.0623 320.1406
-0.98 -1.42 0.30 0.83 -1.69 1.44 0.45 0.00 -0.77 -0.08 0.24 -0.22 3.46 -0.54 -0.75 0.61 2.90 0.31
C19H20F3N3O3 C19H19N3O5S C19H19N3O5S C13H11NO5 C12H15N3O3 C22H24N2O9 C16H18N2O4S C16H18N2O4S C17H22N2O6S C16H18N2O5S C6H10N4 C19H20N2O2 C23H36O7 C21H28O5 C17H20N2S C16H21O2N C13H22N4O3S C18H23NO3 C6H8N4O4
3.58 4.96 5.04 4.19 3.99 3.36 4.50 4.56 4.73 4.87 2.43 6.12 4.54 4.36 4.45 4.15 1.44 3.43 1.55
[M+H]+ [M+CH4OH]+ [M+CH4OH]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+CH4OH]+ [M+CH4OH]+ [M+H]+ [M+H]+ [M-H]− [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ C5H6N3O2+
396.1530 434.1380 434.1380 262.0710 250.1186 461.1555 335.1060 335.1060 383.1271 383.1271 139.0978 309.1598 423.2388 361.2010 285.1420 260.1645 315.1485 302.1751 140.0455
396.1532 434.1383 434.1379 262.0713 250.1186 461.1559 335.1060 335.1061 383.1277 383.1271 139.0976 309.1595 423.2399 361.1996 285.1420 260.1647 315.1485 302.1748 140.0454
0.50 0.69 -0.23 1.14 0.00 0.87 0.00 0.30 1.57 0.00 -0.14 -0.97 2.60 -3.88 0.00 0.77 0.00 -0.99 -0.71
C41H76N2O15 C13H21NO3 C20H17F2N3O3 C43H74N2O14 C21H39N7O12 C13H12N2O3S C8H10N2O3S C10H9ClN4O2S C10H10N4O2S
4.74 1.01 3.69 3.79 0.24 4.30 1.33 3.80 1.63
[M+H]+ [M+H]+ [M+H]+ [M+H]+ C8H19N6O4+ C6H6NO2S+ C6H6NO2S+ [M+H]+ [M+H]+
837.5318 240.1594 386.1311 843.5213 263.1462 156.0114 156.0114 285.0208 251.0597
837.5299 240.1596 386.1306 843.5215 263.1466 156.0108 156.0114 285.0210 251.0597
-2.27 0.83 -1.29 0.24 1.52 -3.85 0.00 0.07 0.00
Lomefloxacin Malachite green Marbofloxacin Mebendazole Meclofenamic acid Mefenamic acid Menadione Metformin Metronidazole Miconazole Minocycline Monensin Naproxen Natamycin Nicotine Nifuroxazide Norfloxacin Orbifloxacin Oxacillin isomer 1 Oxacillin isomer 2 Oxolinic Acid Oxybendazole Oxytetracycline Penicillin G isomer 1 Penicillin G isomer 2 Penicillin V Isomer 1 Penicillin V isomer 2 Pentylenetetrazole Phenylbutazone Pravastatin Prednisolone Promethazine Propanolol Ranitidine Robenidine Ronidazole Roxithromycin Salbutamol Sarafloxacin Spiramycin Streptomycin Sulfabenzamide Sulfacetamide Sulfachloropyridazine Sulfadiazine
Food Anal. Methods Table 1 (continued) Compound
Elemental composition (M) tR (min) Ion
Theoretical m/z Experimental m/z Error (ppm)
Sulfadimethoxyn Sulfadoxine Sulfaguanidine
C12H14N4O4S C12H14N4O4S C7H10N4O2S
4.39 3.94 0.47
[M+H]+ [M+H]+ [M+H]+
311.0809 311.0809 215.0597
311.0805 311.0812 215.0596
-0.13 0.96 -0.46
Sulfamerazine
C11H12N4O2S C11H12N4O3S C12H14N4O2S C9H10N4O2S2 C10H11N3O3S C11H12N4O3S C11H12N4O3S C6H8N2O2S C11H11N3O2S C14H12N4O2S C9H9N3O2S2 C11H13N3O3S C20H17FO3S C22H24N2O8 C7H8N4O2 C7H8N4O2 C12H15Cl2NO5S C46H80N2O13
2.90 3.51 3.32 3.49 3.97 3.53 3.74 0.54 2.68 4.38 2.51 4.14 4.93 3.46 1.08 1.87 3.32 4.02
[M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M-H]− [M+2H]2+
265.0754 281.0703 279.0910 271.0318 254.0594 281.0703 281.0703 173.0379 250.0645 301.0754 256.0209 268.0750 357.0955 445.1605 181.0720 181.0720 353.9975 435.2903
265.0754 281.0701 279.0911 271.0318 254.0594 281.0703 281.0703 173.0380 250.0646 301.0752 256.0210 268.0750 357.0957 445.1601 181.0719 181.0721 353.9964 435.2901
0.00 -0.71 0.36 0.00 0.00 0.00 0.00 0.58 0.40 -0.66 0.39 0.00 0.00 -0.90 -0.55 0.55 -3.11 -0.46
C14H12ClNO2 C15H15NO3 C13H9Cl3ON2 C14H18N4O3 C46H77NO17 C18H24O2
6.39 5.13 6.63 3.22 4.43 5.16
[M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ C18H23O +
262.0629 258.1125 314.9853 291.1452 916.5264 255.1743
262.0633 258.1121 314.9850 291.1451 916.5257 255.1748
1.53 -1.55 -0.95 -0.34 -0.76 1.96
C6H8N2 C20H27O4P C8H11ON C7H10N2O C7H10N2 C8H11N C9H13N C7H10N2 C12H11N C6H6ClN C12H18O2 C6H5NH2
0.29 7.55 1.70 0.41 0.40 1.72 3.27 0.40 4.16 1.60 5.77 0.44
[M+H]+ C12H12O4P + [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+
109.0760 251.0468 138.0913 139.0866 123.0917 122.0964 136.1121 123.0917 170.0964 128.0262 195.1380 94.0651
109.0757 251.0476 138.0912 139.0867 123.0920 122.0963 136.1120 123.0915 170.0962 128.0261 195.1395 94.0655
-2.75 3.19 -0.72 0.72 2.44 -0.82 -2.18 0.81 -1.18 -0.78 7.69 4.25
C19H20O4 C15H16O2 C21H26O5 C21H27ClO5 C21H25ClO4 C21H25ClO4 C21H28O6 C21H24O4 C11H14O3
6.88 5.10 5.25 5.22 6.22 6.41 4.44 6.31 5.45
C7H7+ [M-H]− [M+NH4]+ [M+COOH]− [M+NH4]+ [M+NH4]+ C12H17O3+ [M+NH4]+ [M-H]−
91.0542 227.1078 376.2118 439.1529 394.1780 394.1780 209.1172 358.2013 193.0870
91.0547 227.1079 376.2119 439.1529 394.1774 394.1785 209.1171 358.2011 193.0868
5.49 0.44 0.27 0.00 -1.52 1.27 -0.48 -0.56 -1.04
Sulfameter Sulfamethazine Sulfamethizole Sulfamethoxazole Sulfamethoxypyridazine Sulfamonomethoxine Sulfanilamide Sulfapyridine Sulfaquinoxaline Sulfathiazole Sulfisoxazol Sulindac Tetracycline Theobromine Theophylline Thiamphenicol Tilmicosin Tolfenamic acid Tolmetin Triclocarban Trimethoprim Tylosin ß-Estradiol Food-packaging contaminants 1,3-Phenylenediamine 2-EHDP 2-Methoxy-5-methylalanine 2,4-Diaminoanisole 2,4-Diaminotoluene 2,4-Dimethylaniline 2,4,5-Trimethylaniline 2,6-Diaminotoluene 4-Aminobiphenyl 4-Chloroaniline 4-Hexylresorcinol Aniline Benzyl butyl phthalate Bisphenol A BA(2,3-DHP)GE BA(3Cl,2HP)(2,3DHP)E BA(3Cl2HP)GE isomer 1 BA(3Cl2HP)GE isomer 2 BAB(2,3DHP)E Bisphenol A diglycidyl ether Butyl p-hydroxybenzoate
Food Anal. Methods Table 1 (continued) Compound
Elemental composition (M) tR (min) Ion
Theoretical m/z Experimental m/z Error (ppm)
Di (2-ethylhexyl)adipate (DEHA) Dibutyl sebacate Dicyclohexyl phthalate
C22H42O4 C18H34O4 C20H26O4
8.77 7.95 7.64
[M+Na]+ [M+H]+ C8H5O3+
393.2975 315.2530 149.0233
393.2980 315.2536 149.0230
1.27 1.90 0.67
Diethyl phthalate
C12H14O4 C28H46O4 C26H42O4 C10H10O4 C16H22O4 C24H38O4 C24H38O4 C14H18O4 C9H10O3 C3H6N6 C8H8O3 C4H11NO C18H22O4 C7H9ON C7H9N C10H12O3 C20H34O8 C12H27PO4
5.50 9.65 8.96 4.71 6.97 8.88 8.94 6.29 4.58 0.26 4.08 0.41 5.17 0.65 0.79 5.06 7.38 6.43
C8H5O3+ [M+H]+ [M+H]+ C9H7O3+ C8H5O3+ [M+H]+ [M+H]+ C8H5O3+ [M-H]− [M+H]+ [M-H]− [M+H]+ [M-H]− C6H7NO+ [M+H]+ [M-H]− [M+H]+ H4PO4+
149.0233 447.3469 419.3156 163.0390 149.0233 391.2843 391.2843 149.0233 165.0557 127.0727 151.0401 90.0913 301.1445 109.0522 108.0808 179.0714 403.2326 98.9842
149.0240 447.3479 419.3156 163.0391 149.2040 391.2843 391.2847 149.0236 165.0556 127.0733 151.0413 90.0912 301.1462 109.0525 108.0811 179.0710 403.2333 98.9847
4.70 2.24 0.00 0.61 4.70 0.00 1.02 2.01 -0.61 4.72 7.94 -1.11 5.65 2.75 2.78 -2.23 1.79 5.05
4.03 5.65
H4PO4+ C4H9Cl2O3+
98.9842 174.9923
98.9847 174.9922
5.05 -0.57
3.84 4.66 4.49 4.51 4.32 4.18 5.22 5.03 6.11 2.37 4.56 4.30 4.40 4.41 4.78 4.45
[M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ C18H23O4+ [M+H]+ [M+H]+ [M+H]+ [M+Na]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ C13H15N2O4+
339.1438 313.0707 315.0863 329.0656 331.0812 329.0656 303.1591 251.0914 337.1547 297.1333 389.1571 562.3024 562.3024 722.3957 706.4008 263.1026
339.1447 313.0704 315.0861 329.0656 331.0813 329.0657 303.1593 251.0915 337.1549 297.1340 389.1571 562.3016 562.3017 722.3934 706.3995 263.1030
2.65 -0.96 -0.63 0.00 0.30 0.30 0.66 0.40 0.59 2.36 0.00 -1.42 -1.24 -3.18 -1.84 1.52
C22H32O8 C20H18ClNO6 C7H6O4 C18H12O6 C24H34O9 C18H22O5
4.77 5.63 1.09 5.81 5.40 5.66
[M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+Na]+ [M+H]+
425.2170 404.0895 155.0339 325.0707 489.2095 319.1540
425.2169 404.0890 155.0341 325.0704 489.2096 319.1539
-0.24 -1.24 1.29 -0.92 0.20 -0.31
C3F5HO2 C4F7HO2
0.81 2.96
C2F5− C3F7−
118.9926 168.9894
118.9927 168.9898
0.84 2.37
Diisodecyl phthalate Diisononyl phthalate Dimethyl phthalate Di-N-butyl phthalate Di-N-octyl phthalate iso. 1 Di-N-octyl phthalate iso. 2 Dipropyl phthalate Ethyl 4-hydroxybenzoate Melamine Methyl paraben N,N-diethylhydroxylamine Nordihydroguaiaretic acid o-Anisidine o-Toluidine Propyl 4-hydroxybenzoate Tributyl o-acetylcitrate Tributyl phosphate Triethyl phosphate
C6H15O4P Tris(chloropropyl)phosphate (TCPP) C9H18Cl3O4P Mycotoxins 3-Acetyldeoxynivalenol C17H22O7 C17H12O6 Aflatoxin B1 C17H14O6 Aflatoxin B2 C17H12O7 Aflatoxin G1 C17H14O7 Aflatoxin G2 C17H12O7 Aflatoxin M1 Alfa zearalenol C18H24O5 Citrinin C13H14O5 Cyclopiazonic acid C20H20N2O3 Deoxynivalenol C15H20O6 Diacetoxyscirpenol C19H26O7 Ergocornine isomer 1 C31H39N5O5 Ergocornine isomer 2 C31H39N5O5 C34H59NO15 Fumonisin B1 C34H59NO14 Fumonisin B2 Gliotoxin C13H14N2O4S2 HT-2 toxin Ochratoxin A Patulin Sterigmatocystin T2-toxin Zearalenone Perfluorinated compounds C3 pentafluoropropionic acid C4 perfluorobutyric acid
Food Anal. Methods Table 1 (continued) Compound
Elemental composition (M) tR (min) Ion
Theoretical m/z Experimental m/z Error (ppm)
C5 perfluoropentanoic acid C7 perfluoroheptanoic acid C8 perfluorooctanoic acid
C5HO2F9 C7HO2F13 C8F15O2H
4.09 5.05 5.47
C4F9− C6F13− C7F15−
218.9862 318.9798 368.9766
218.9867 318.9814 368.9781
2.28 5.02 4.07
C9 perfluorononanoic acid C10 perfluorodecanoic acid C11 perfluoroundecanoic acid C12 perfluorododecanoic acid
C9F17O2H C10F19O2H C11F21O2H C12F23O2H C8HSO3F17
5.89 6.33 6.81 7.35 6.66
C8F17− C9F19− C10F21− C11F23− [M-H]−
418.9734 468.9702 518.9670 568.9638 498.9302
418.9755 468.9714 518.9682 568.9629 498.9327
5.01 2.56 2.31 -1.58 5.01
C4H10N2O C2N2H6O C8H18N2O C6H14N2O C3H8N2O C4H8N2O2 C12H10N2O C5H10N2O C4H8N2O
2.24 0.51 5.75 4.62 0.89 0.75 5.94 2.96 0.96
[M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ [M+H]+ C9H11N+ [M+H]+ [M+H]+
103.0866 75.0553 159.1492 131.1174 89.0709 117.0659 169.0886 115.0866 101.0709
103.0862 75.0556 159.1494 131.1177 89.0715 117.0660 169.0885 115.0866 101.0710
3.88 4.00 1.26 -1.53 6.74 0.85 -0.94 0.00 0.99
C14H18N2O5 C4H5NO4S
3.38 0.63
[M-H]− [M-H]−
293.1143 161.9867
293.1152 161.9871
3.07 2.47
C7H5NO3S C12H19Cl3O8 C6H12NO3S
1.25 3.40 1.45
[M-H]− [M-H]− [M-H]−
181.9917 395.0073 178.0538
181.9921 395.0091 178.0538
2.20 4.56 0.00
Heptadecafluorooctane sulfonic acid Nitrosamines N-nitrosodiethylamine N-nitrosodimethylamine N-nitrosodi-n-dibutylamine N-nitrosodi-n-dipropylamine N-nitrosomethylethylamine N-nitrosomorpholine N-nitroso-n-diphenylamine N-nitrosopiperidine N-nitrosopyrrolidine Sweeteners Aspartame Acesulfame Saccharin Sucralose Cyclamate
2-EHDP 2-ethylhexyl diphenyl phosphate, BA(2,3-DHP)GE bisphenol A (2,3-dihydroxypropyl) glycidyl ether, BA(3Cl,2HP)(2,3DHP)E bisphenol A (3-chloro-2-hydroxypropyl) (2,3-dihydroxypropyl) ether, BA(3Cl,2HP)GE bisphenol A (3-chloro,2-hydroxypropyl) glycidyl ether, BAB (2,3DHP)E bisphenol A bis(2,3-dihydroxypropyl) ether
Agilent Technologies, Santa Clara, CA, USA), consisting of a vacuum degasser, an autosampler, and a binary pump. Mobile phases A and B were water and acetonitrile, respectively, both with 0.1 % formic acid. The flow rate used was 0.5 mL min−1. The chromatographic method held the initial mobile phase composition (5 % B) constant for 2 min, followed by a linear gradient to 100 % B at 8 min and held constant for a 2 min at 100 % B. Twenty microliters of extract was injected in each study. A 5-min post-time was used for each analysis. The UHPLC system was connected to a quadrupoletime-of-flight mass spectrometer Agilent Q-TOF 6530 (Agilent Technologies, Santa Clara, CA, USA) equipped with an electrospray interface operated in either positive or negative ionization mode, using the following operation parameters: capillary voltage, 4000 V; nebulizer pressure, 40 psig; drying gas, 9 L min−1; gas temperature, 325 °C; and fragmentor voltage, 90 V. LC-MS accurate mass spectra were recorded across the range m/z 50–1000. Two different experiments were conducted, full-scan acquisition and all-ion mode MS/MS, in order to perform
CID experiments in a dedicated collision cell with no precursor ion isolation along with high-resolution fullscan acquisition. All-ion mode full-scan acquisition was used at two different collision energy conditions (0 (full scan with no fragmentation) and 20 V), using 400 ms for each experiment (1.25 spectra/acquisition points per second). Accurate mass measurements of each peak from the total ion chromatograms were obtained by means of an automated calibrant delivery system using a dual-nebulizer electrospray source that introduces the flow from the outlet of the chromatograph together with a low flow of a calibrating solution (calibrant solution A, Agilent Technologies), which contains the internal reference masses (purine (C5H4N4 at m/z 121.050873 and HP-0921 [hexakis-(1H,1H,3Htetrafluoropentoxy)-phosphazene] (C18H18O6N3P3F24) at m/z 922.009798). All data was recorded with Agilent MassHunter Data Acquisition software (version B.04.00) and processed with Agilent MassHunter Qualitative Analysis software (version B.04.00), which included both Molecular Feature Extractor and Find by Formula applications used.
Food Anal. Methods
Food Anal. Methods
Fig.
1 a Total ion chromatograms (TICs) of a pesticide mixture (100 μg kg−1) in orange using elution gradients A (a1), B (a2), and C (a3). b Extracted ion chromatograms (EICs) of some database compounds (imazalil, diphenylamine, tebuconazole, difenoconazole, prometon, and prometryn (100 μg L−1) in orange with elution gradients A (b1), B (b2), and C (b3)
Development of an Accurate Mass Database of 630 Multiclass Food Contaminant Pollutants Mixtures containing ca. 30–50 compounds, at individual concentrations of 200 μg L−1 each, were injected in the UHPLC-QTOFMS system to collect retention time (tR) data and the accurate masses of target ions together with the elemental composition. For confirmatory purposes, the mass spectra acquired using all-ion mode acquisition were carefully investigated to identify characteristic fragment ions. In some cases, individual standards of target compounds were required for further confirmation of diagnostic fragment ions. For the screening method step, an Excel spreadsheet was constructed containing for each analyte the compound name, molecular formula, theoretical exact mass, fragment ions, and retention time. This file was converted into csv format for use by the Agilent MassHunter Data Acquisition software (version B.04.00). When a sample run is completed and the corresponding raw data acquired, its components are automatically matched against the csv file (Find by formula application) by the MassHunter software taking into account a defined tolerance for mass and retention time deviations (tR ± 0.25 min and ion exact mass ± 10 ppm), and a report is generated with the compounds tentatively found in the analyzed sample data file.
Results and Discussion Screening Method Development and General Acquisition Method Considerations Selection of UHPLC Gradient Before developing the screening method, different elution gradients were assayed using matrix-matched standards in representative matrices (such as tomato and orange) in order to obtain appropriate separation of analytes and matrix components within the shortest time period while displaying relatively low or moderate signal suppression effects. Three methods (A, B, and C) were assayed by varying the total gradient time, using the same flow rate (0.5 mL min−1) and mobile phases (total time of 5, 10, and 15 min, respectively). Mobile phases were 0.1 % HCOOH in water (A) and 0.1 % HCOOH in acetonitrile (B). The details of the different gradient elution programs are shown in Table S1 (Electronic Supplementary Material (ESM)). An example on the analysis of a mixture of selected pesticides in orange and some representative extracted ion chromatograms (EICs) (100 μg kg−1) are shown in Fig. 1.
To develop the screening method, different criteria were employed to select the most appropriate elution gradient. The comparison of the total ion chromatograms (TICs) revealed that the matrix components and analytes were not separated properly with the shortest method. The number of coelutions and thus the possibility of interferences and quantitation issues due to matrix effects would be clearly increased under these conditions (method A). It must be taken into account the large number of components from a matrix (typically with 5000–10,000 (Gómez-Ramos et al. 2013; GómezRamos et al. 2016) at relevant concentrations which must be separated. For this reason, the shortest method (method A) was discarded. Given the differences of run time, it would be expected that coelutions with method B were more frequent than with method C. This fact was further examined using matrix effects. Matrix effects were evaluated using 15 representative analytes (including pesticides, veterinary drugs, and mycotoxins) in tomato and orange matrices with the two remaining methods (B and C). Matrix effects were calculated as follows: [(calibration curve slope in matrix / calibration curve slope in solvent) − 1] × 100. Positive values indicate signal enhancement while negative signal involves values suppression—the more common phenomenon. Depending on this percentage, matrix effect was classified in different categories, according to previous literature (Ferrer-Amate et al. 2010; GonzálezAntuña et al. 2013). A percentage between −20 and 20 % was considered as mild matrix effect, as the slope ratios matrix/solvent would be approaching the unit. A medium matrix effect occurred when this percentage was from −50 to −20 % or from +20 to +50 %. Strong matrix effect would be produced when this percentage was below −50 % or above +50 %. As shown in Fig. 2a, all the selected compounds showed signal suppression in tomato with both elution gradients B and C, with the exception of aflatoxin B1, thiabendazole, and azoxystrobin. The extent of matrix effects was not significantly different between the two gradients (B and C). In the case of orange (Fig. 2b), all tested compounds showed signal suppression with both elution gradients assayed, although, in general, the matrix effects are slightly less intense in the case of the longer method. This is consistent with the fact that there is more time to separate species, thus minimizing the potential coelutions and the associated ionization competition and subsequent matrix suppression. As the main objective was to develop a screening method which separate and identify the most number of compounds in a single run in the shortest time possible, elution gradient B was selected. Identification of the Targeted Species by UHPLC-QTOFMS A generic full-scan acquisition method with default source parameters was used for the mass spectrometric detection of the studied species. Default values were set for drying
Food Anal. Methods
Fig. 2 a Percentages of signal suppression or enhancement for selected compounds in tomato (A aflatoxin B1; B azoxystrobin; C buprofezin; D carbendazim; E cyromazine; F DEET; G diuron; H imazalil; I imidacloprid; J prochloraz; K sarafloxacin; L sulfamethoxazole; M tebuconazole; N tetracycline; O thiabendazole; R thiacloprid). b
Percentages of signal suppression or enhancement for selected compounds in orange (A aflatoxin B1; B azoxystrobin; C buprofezin; D carbendazim; E cyromazine; F DEET; G diuron; H imidacloprid; I prochloraz; J sarafloxacin; K sulfamethoxazole; L tebuconazole; M tetracycline; N thiabendazole; O thiacloprid)
and nebulizer flow rates and pressures and drying gas temperatures considering the LC flow rate and mobile phase composition. The identification of the target species was carried out using retention time values and accurate mass measurements of the (de)protonated molecules in most cases. Exceptionally, either sodium or ammonium adducts were identified as the most abundant ion for a few compounds (4 %). In general, 90 % of compounds were detected in positive ion mode
whereas only 10 % of targeted compounds were identified in negative ionization mode. Additionally, for ca. 20 % of the species, it was found that fragments generated—from insource CID during ion transportation—were more abundant than the corresponding (de)protonated molecules. The detailed information including detected ion, elemental composition, retention time, theoretical m/z (exact mass), and experimental measured accurate masses with the relative mass error (expressed in ppm) are shown in Table 1, where compounds
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are grouped according to their class (pesticides, veterinary drugs, mycotoxins, perfluorinated compounds, foodpackaging contaminants, nitrosamines, and sweeteners). For confirmation of the species, acquisition with the UHPLC-QTOFMS instrument was undertaken in the Ball-ion mode^ acquisition mode. This consists on the use of CID fragmentation in a collision cell without previous precursor isolation, so that all ions entering the mass spectrometer are subjected to thorough fragmentation, thus avoiding restrictions on the number of coeluting compounds subjected to MS/MS and also previous information required information to conduct the MS/ MS experiments such as retention time windows or precursor ion masses. The acquisition method proposed consisted on two full-scan experiments with the collision cell different collision energies: 0 V (no fragmentation) and 20 V Fig. 3 a Csv file with relevant information (elemental composition, retention time, exact mass, compound name for the main ion of each compound) for the automatic search of compounds with Agilent MassHunter Qualitative Analysis software. b Selection of mass error tolerance and retention time window for the automatic search using the specific software
(fragmentation), using an acquisition time of 400 ms for each experiment. With such experiments, at least two ions were obtained for identification/purposes in most cases with the exception of few low molecular weight molecules, difficult to fragment. Study of Searching Parameters for Automated Screening A snapshot of the software application used (Find by Formula tool, Agilent MassHunter Qualitative Analysis (version B.04.00)) is shown in Fig. 3 along with the main information included in the database. The main search parameters (accurate mass tolerance and retention time (tR) window) affecting the performance of the automated search using Find by Formula tool were carefully examined. Different experiments were assayed varying tR windows (±0.05, ±0.1, ±0.25,
Food Anal. Methods
±0.5 min) with two fixed accurate mass tolerances (±5 or ±10 ppm). Default settings of peak filtering were used to remove background and mobile phase ion contribution. In these experiments, the database (630 compounds) was applied to 16 synthetic mixtures of pesticides (100 μg L−1) with 30 compounds each. The number of false positives and negatives, average score (%), and success rate (%) were evaluated for each mixture. The term false positive meant that a compound was reported, but it was not present in the actual sample. On the other hand, a compound which was present in the synthetic mixture but not reported by the software after the automated search was a false negative.
In most cases, false negatives were due to two main reasons: (i) detector saturation occurring with high sensitive compounds or compounds at high concentrations and (ii) low sensitivity compounds with very low response factors—those which do not really perform properly mainly because of poor electrospray ionization. In the first scenario, spectra obtained displayed low score values due to accurate mass drifting with saturated detector and also due to the spectra collected which was not statistically representative of the sample. In the latter case, the concentration tested (100 μg L−1) was not high enough to detect the compounds, and thus, they were reported as false negatives.
Fig. 4 a Number of false positives reported by the software when retention time windows varied from ±0.05 to ±0.5 min, using ±5 ppm as mass error tolerance. b Number of false positives reported by the
software when retention time windows varied from ±0.05 to ±0.5 min, using ±10 ppm as mass error tolerance
Food Anal. Methods
Subtle differences were found in terms of the number of false negatives, average score, and success rate for each mixture using the experiments at different retention time and mass bias. In contrast, significant differences were found in the number of false positives, when different retention time windows were employed with ±5 and ±10 ppm as mass error tolerance. The results in terms of false positive rates obtained for each of the synthetic mixture tested (using ±5 and ±10 ppm as mass error tolerance) are shown in Fig. 4. The results are expressed in number of false positives (out of 630) related to the number of compounds expected (30 in each experiment). The data collected concluded that wider retention time windows yielded a higher value of false positives. The highest number of compounds was reported when ±0.5 min was used and the lowest with ±0.05 min. Those results did not depend heavily on the mass error tolerance employed. In this sense, it should be kept in mind that complex food extracts may shift the retention times so that these results may be affected, particularly in the case of early eluting compounds (more affected by matrix, pH, and/or composition). For this reason, the narrowest retention time tolerance (± 0.05 min) was discarded. On the other hand, the results obtained using ±0.1 and ±0.25 min tolerances were relatively similar with minor differences in the number of false positives. Both tolerances could be adopted for the final method, although, in order to prevent false negatives due to retention time shifts particularly for polar compounds, and also due to relatively high mass errors obtained for small molecules with m/z lower than 150, ±0.25 min and ±10 ppm were finally selected as the most appropriate retention time window and mass error tolerance for screening step. Eventually, a final additional step would involve confirmation of the findings and accurate mass measurements of ions and fragments for each tentative compound detected, which would be within the widely accepted standard 5-ppm relative mass error threshold (or 1 mDa for molecules below 200 Da) (European Commission 2015)). Analytical Performance Three representative food matrices (tomato, orange, and baby food) were employed to evaluate the performance of the proposed screening method in terms of linearity, matrix effects, and limits of quantification (LOQs). In order to avoid coelutions between analytes that could shift
Fig. 5 Percentage of database compounds classified according to their LOQs in tomato, orange, and baby food
the actual performance in terms of matrix effects, mixtures containing ca. 30 compounds (each) were used to prepare the calibration curves in the concentration range from 1 to 1000 μg kg−1 (1, 10, 50, 100, 200, 500, and 1000) in solvent standards (20 % methanol), tomato, orange, and baby food extracts. LOQs were estimated as the minimum concentration of analyte corresponding to a signal-to-noise ratio (S/ N) = 10:1. This was experimentally calculated from the injection of matrix-matched standards at low concentration levels, using the more abundant ion for each extracted ion chromatograms with narrow mass windows (±10 ppm relative mass error). In the case of pesticides, sample extracts were prepared by spiking samples before sample extraction step so that recovery percentages were considered. Results obtained for pesticides are detailed in Table S-2 (ESM), along with the maximum residue level (MRLs) established for the pesticide/ commodity combinations tested. The data for the rest of classes studied is included in Table S-3 (ESM). They are also summarized in Fig. 5, and the overall data of LOQs for each individual group of compounds is included as Supplementary material (Figs. S1–S2). Most of pesticides and veterinary drugs showed limits of quantification from 1 to 10 μg kg−1 in tomato, orange, and baby food. The percentage of those compounds with LOQs < 1 μg kg−1 was higher in baby food and tomato than in orange. On the other hand, 65 % of foodpackaging contaminants displayed LOQs <10 μg kg−1 in baby food. In tomato and orange, most of those compounds exhibited LOQs from 10 to 100 μg kg −1. For the rest of compound classes tested (food-packaging contaminants, mycotoxins, and perfluorinated compounds), the highest percentage of compounds with LOQs > 10 μg kg −1 was obtained in orange extracts. This can be attributed to the complexity of the orange matrix (and the extent of matrix effects therein) compared to both tomato and baby food matrices, as clearly illustrated in Fig. 6. Examples of compounds detected in incurred food samples are shown in Fig. 7, where the extracted ion chromatograms and mass spectra of tebuconazole and imazalil detected in peach jam and oranges, respectively, are shown. In the case of the pesticides, the LOQs obtained were contrasted with the MRLs for the pesticide/commodity combinations available. Considering the default MRLs for
Food Anal. Methods Fig. 6 a Overlapped total ion chromatograms (TICs) of a pesticide mixture (100 μg L−1) in solvent, tomato, orange, and baby food. b Overlapped extracted ion chromatograms (EICs) of metribuzin (100 μg kg−1) in solvent, tomato, orange, and baby food. c Overlapped extracted ion chromatograms (EICs) of fluquinconazole (200 μg kg−1) in solvent and tomato
pesticides in baby food set at 10 μg kg −1, over 90 % of the compounds fulfilled this threshold, being 56 above the value set, either because they were not recovered (e.g., highly polar compounds requiring dedicated sample treatment) or because of lower response factors. In the latter case, the compounds are
low sensitive due to poor ionization with electrospray. As has been reported by other authors, there is always a percentage in the range of 10 %, which does not yield good response factors due to its features not compatible to electrospray (Alder et al. 2011; García-López et al. 2014), even despite using state-of-
Food Anal. Methods
Fig. 7 a Extracted ion chromatogram (EIC) of tebuconazole in solvent (20 % methanol) (a1), mass spectrum of tebuconazole in solvent (20 % methanol) (a2), extracted ion chromatogram (EIC) of tebuconazole in peach jam (a3), and mass spectrum of tebuconazole in peach jam (a4).
b Extracted ion chromatogram (EIC) of imazalil in solvent (20 % methanol) (b1) and mass spectrum of imazalil in solvent (20 % methanol) (b2). Extracted ion chromatogram (EIC) of imazalil in orange (b3) and mass spectrum of imazalil in orange (b4)
Food Anal. Methods
the-art instrumentation in some of the studies. In the case of tomato, despite 75 compounds (18 % out of 411 pesticides included) did not achieve the 10-μg kg −1 sensitivity, only 47
Fig. 8 2D plot representing matrix effects for the different compounds tested in a tomato, b orange, and c baby food. For details, see text
were above the MRL value set (10 %), 24 not recovered, and 23 with LOQs above MRLs. Finally, in the case of orange, around 30 % was above the 10-μg kg −1 threshold, with 85
Food Anal. Methods
compounds (20 %) not fulfilling the MRL requirements. These results evidence one of the limitations of this type of screening approaches. The sensitivity is yet an issue, and this is more evident as the matrix complexity increases. With the use of state-of-the-art instrumentation, using heated electrospray source providing a remarkable sensitivity increase, there will always be a percentage of Bdifficult to ionize^ compounds that would not fulfill the sensitivity requirements. Besides the performance in terms of LOQs, matrix effects were also tested. Matrix effects usually occur during ionization step, where the matrix constituents influence the ionization of coeluted analyte(s). Coelution with matrix interferences or with compounds belonged to the same batch could produce signal suppression or enhancement of the target compounds. This fact also could cause mass measurement deviations from theoretical m/z values. As an example, Fig. 6b includes the extracted ion chromatograms of a pesticide (metribuzin, 100 μg kg−1) in solvent, tomato, orange, and baby food. Signal suppression was observed in these three matrixes. Orange was the one that produced the highest signal suppression, followed by tomato and baby food. Figure 6c shows EICs for fluquinconazole in solvent and tomato. For this compound, signal enhancement was observed in matrix (200 μg kg−1), although this is not the standard behavior. The same criterion—described previously—was applied for matrix effect evaluation. Slope ratios of matrix/solvent from 0.8 to 1 were considered as soft signal suppression, from 0.5 to 0.8 medium signal suppression, and lower than 0.5 strong signal suppression. Signal enhancement could also be classified as soft (slope ratios of matrix/solvent from 1 to 1.2), medium (slope ratios of matrix/solvent from 1.2 to 1.5), and strong (slope ratios of matrix/solvent from 1.5 to 2). Figure 8 includes a 2D plot representing the matrix effects obtained for all the tested compounds in the three different matrices tested. Table S4 and Fig. S2 (Supplementary data) include the data from the matrix effects displayed by the different classes of compounds, being signal suppression the most common effect produced in tomato, orange, and baby food. Medium signal suppression was the most common effect produced in tomato for pesticides, mycotoxins, veterinary drugs, food-packaging contaminants, and nitrosamines, with the exception of perfluorinated compounds and sweeteners. Results for orange were distinctly worse than the other two matrices, with average suppression of 30–40 % as illustrated in Fig. 8b. These results are consistent with previous studies (Gómez-Ramos et al. 2016) and may be attributed, perhaps, to the complexity of the orange matrix due to its composition and the presence of waxes and citrus oils. Finally, soft signal suppression for pesticides, veterinary drugs, mycotoxins, food-packaging contaminants, and sweeteners was the most common effect produced in baby food. This is consistent with the complexity of each of the matrix revealed by the TIC profiles shown (Fig. 6). As an alternative, the use of longer column (e.g., 100 mm) and longer gradient may help to reduce
matrix effects as it would enable a better separation, at the expense of method throughput though.
Conclusions A screening method using UHPLC-QTOFMS has been developed for the examination of 630 food contaminants, including pesticides, veterinary drugs, food-packaging contaminants, mycotoxins, nitrosamines, perfluorinated compounds, and sweeteners. The method was based on a database with retention time values and mass accurate measurements of the ions of interest. It was found that software parameters such as retention time window and mass error tolerance have a clear influence on the automatic search results. The proposed methodology was also examined in terms of linearity, matrix effect, and limits of quantification in three different matrixes: tomato, orange, and baby food. For most of compounds, signal suppression was the most common matrix effect produced. In general, baby food and orange produced the lowest and the highest matrix effect, respectively. This clearly had an impact on the sensitivity of the method. Limits of quantification were also calculated for the 630 compounds included, and most of them were <10 μg kg−1 in tomato, orange, and baby food. However, in the particular case of pesticides with relatively low response factors (ca. 10–20 % of the compounds depending on the complexity of the matrix), the detection was not fulfilling the MRL established for the tested pesticide/ commodity combination. This is a drawback of the entire approach that may be partially solved with more sensitive and updated instrumentation, except for the case of compounds not really amenable to electrospray ionization. Acknowledgments The authors acknowledge funding from the Spanish Ministerio de Economía y Competitividad (MINECO) (Ref. CTQ-2009-10897). P.P.-O acknowledges a PhD scholarship from the University of Jaén. F.J.L.-O. acknowledges a FPI Program PhD scholarship from MINECO (Ref. BES-2013-064014). D.M.G. thanks the MINECO for a Juan de la Cierva postdoctoral contract. B.G.L. acknowledges MINECO for her Juan de la Cierva postdoctoral research contract (Ref. JCI-2012-12972). The authors acknowledge Servicios Centrales de Apoyo a la Investigación of the University of Jaen (SCAI-UJAEN). Compliance with Ethical Standards Conflict of Interest Patricia Pérez-Ortega declares that she has no conflict of interest. Felipe J. Lara-Ortega declares that he has no conflict of interest. Bienvenida Gilbert-López declares that he has no conflict of interest. David Moreno-González declares that he has no conflict of interest. Juan F. García-Reyes declares that he has no conflict of interest. Antonio Molina-Díaz declares that he has no conflict of interest. Ethical Approval This article does not contain any studies with human participants or animals performed by any of the authors. Informed Consent Not applicable.
Food Anal. Methods
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