SUPPLEMENTARY INFORMATION to the Paper Entitled

SUPPLEMENTARY INFORMATION to the paper entitled:

Evaluation of the potential of GC-APCI-MS for the analysis of pesticide residues in fatty matrices

María Luz Gómez-Pérez, Patricia Plaza-Bolaños, Roberto Romero-González, José Luis Martínez Vidal, Antonia Garrido Frenich*

Research Group “Analytical Chemistry of Contaminants”, Department of Chemistry and Physics,Research Centre for Agricultural and Food Biotechnology (BITAL), University of Almería, Agrifood Campus of International Excellence, ceiA3, E-04120 Almería, Spain.

* Corresponding author. Tel: +0034950015985; fax: +0034950015008.

E-mail address: (A. Garrido Frenich).

This document provides more detailed information to the main paper mentioned above.

The following information is included:

ContentPage

Additional information about experimental issuesS-2

Table 1S-4

Table 2S-7

Figure 1S-10

Figure 2S-11

Figure 3S-12

Additional information about experimental issues

Optimization of the extraction procedure

The use of a generic extraction method that allowed the determination of a high number of compounds was preferred. For the optimization of the extraction procedure, blank composed meat samples (a homogenized mixture containing the three types of meat highly consumed in the EU: beef, pork and chicken) were used for the preparation of matrix-matched standards and spiked samples.

Method Validation

A validation protocol was carried out in order to establish the performance characteristics of the method to ensure the adequate detection and quantification of the target compounds. Several parameters such as linearity, intra-day precision, inter-day precision, trueness (expressed as recovery), and limits of detection (LODs) and quantification (LOQs) were studied.

Matrix effect was evaluated by analyzing calibration sets prepared in solvent (from 3 to 100 µg/L) and in extracted blank meat (matrix-matched calibration) at the same concentrations.

Linearity was then evaluated in the range 3-100 µg/L.

Trueness was estimated in terms of recovery by evaluating three different concentration levels (10, 50 and 150 µg/kg). Five blank samples were fortified at each level.

Precision was evaluated by performing repeatability (intra-day precision) and reproducibility (inter-day precision) studies. Repeatability was studied by analyzing five spiked blank samples at different fortification levels (10, 50 and 150 µg/kg) extracted in the same day. Inter-day precision (reproducibility) was studied by analyzing three spiked blank samples at 50 µg/kg extracted in 5 consecutive days.

The identification of the target compounds was based on retention time windows (RTWs), which were defined as the RT average plus or minus 3 times the standard deviation (SD) of the RT (RT ± 3 SD) when five spiked samples at 50 µg/kg were injected.

LODs were estimated by analyzing spiked blank samples at nine different concentration levels (1, 3, 5, 7, 10, 25, 50, 150 and 300 µg/kg). The criteria used for determining them were the RTW, isotopic pattern and mass error ( > 5 ppm, absolute value).

LOQs were determined as the minimum concentration that provides suitable recovery (70-120 %) with acceptable precision. Therefore, if a compound was recovered at 10 µg/kg, this concentration value was set as its LOQ.

Table 1. GC-APCI-MS parameters of the compounds

Pesticide / Molecular formula / Monitored ion / Theoretical
mass / RTW
(min) / Mass error (ppm)
Acephate / C4H10NO3PS / M+• / 183.9999 / 17.62-17.78 / -2.7
Aclonifen / C12H9ClN2O3 / [M+H]+ / 265.0380 / 16.08-16.26 / -1.6
Acrinathrin / C26H21F6NO5 / M+• / 541.1323 / 17.77-17.90 / 1.2
Aldrin / C12H8Cl6 / M+• / 361.8757 / 14.69-14.75 / 4.8
Azinphos methyl / C10H12N3O3PS2 / M+• / 317.0058 / 15.41-17.77 / 4.1
Benalaxyl / C20H23NO3 / [M + H]+ / 326.1756 / 16.20-16.62 / 3.1
Bifenox / C14H9Cl2NO5 / M+• / 340.9858 / 17.35-17.47 / 0.9
Bifenthrin / C23H22ClF3O2 / [M + H]+ / 423.1339 / 17.10-17.22 / 2.4
Boscalid / C18H12Cl2N2O / [M + H]+ / 343.0405 / 19.12-19.20 / 1.6
Bupirimate / C13H24N4O3S / [M + H]+ / 317.1647 / 15.54-15.70 / -4.6
Buprofezin / C16H23N3OS / [M + H]+ / 306.1640 / 15.56-15.74 / 1.0
Chlordane / C10H6Cl8 / [M + H]+ / 406.8056 / 15.20-15.41 / 4.3
Chlorfenson / C12H8Cl2O3S / [M + H]+ / 302.9649 / 15.36-15.52 / 3.8
Chlorfenvinfos / C12H14Cl3O4P / [M + H]+ / 358.9774 / 14.67-14.89 / 4.2
Chlorpyrifos methyl / C7H7Cl3NO3PS / [M + H]+ / 321.9028 / 13.49-13.62 / 3.1
Chlorthal dimethyl / C10H6Cl4O4 / [M + H]+ / 330.9099 / 14.21-14.33 / 1.8
Cyfluthrin / C22H18Cl2FNO3 / [M + H]+ / 434.0726 / 18.90-19.01 / 2.8
Cyproconazole / C15H18ClN3O / [M + H]+ / 292.1217 / 15.75-15.94 / -0.3
Cyprodinil / C14H15N3 / [M + H]+ / 226.1344 / 14.54-14.73 / 2.7
Diazinon / C12H21N2O3PS / [M + H]+ / 305.1089 / 12.71-12.99 / 1.0
Dichlobenil / C7H3Cl2N / [M + H]+ / 171.9721 / 9.10-9.28 / -2.9
Dicloran / C6H4Cl2N2O2 / [M + H]+ / 205.9650 / 12.39-12.51 / 4.4
Dieldrin / C12H8Cl6O / [M + H]+ / 378.8784 / 15.89-16.05 / 4.1
Diethofencarb / C14H21NO4 / M+• / 267.1471 / 14.06-14.24 / 4.7
Diflufenican / C19H11F5N2O2 / [M + H]+ / 395.0819 / 16.66-16.84 / -4.4
Diniconazole / C15H17Cl2N3O / [M + H]+ / 326.0827 / 16.00-16.12 / 1.2
Disulfoton sulfone / C8H19O4PS3 / [M + H]+ / 307.0261 / 15.12-15.31 / 3.9
Endosulfan / C9H6Cl6O3S / [M + H]+ / 404.8247 / 15.28-15.40 / 4.9
Endrin / C12H8Cl6O / M+• / 377.8706 / 15.62-15.71 / 3.2
Etridiazole / C5H5Cl3N2OS / [M + H]+ / 246.9266 / 10.09-10.26 / 4.5
Fenamiphos / C13H22NO3PS / [M + H]+ / 304.1136 / 15.21-15.40 / -3.6
Fenamiphos sulfoxide / C13H22NO4PS / M+• / 319.1007 / 17.69-17.80 / 3.2
Fenarimol / C17H12Cl2N2O / [M + H]+ / 331.0405 / 18.05-18.11 / 1.3
Fenoxycarb / C17H19NO4 / [M + H]+ / 302.1392 / 17.16-17.36 / 4.9
Fenthion / C10H15O3PS2 / [M + H]+ / 279.0279 / 14.17-14.31 / 2.9
Fenthion sulfoxide / C10H15O4PS2 / [M + H]+ / 295.0228 / 15.92-16.10 / -2.8
Fenvalerate / C25H22Cl2N2O / M+• / 419.1288 / 19.90-20.01 / 3.4
Fipronil / C12H4Cl2F6N4OS / [M + H]+ / 436.9465 / 14.57-14.70 / 4.7
Fluazifop-P-butyl / C19H20F3NO4 / [M + H]+ / 384.1423 / 15.79-15.90 / -4.5
Fludioxonil / C12H6F2N2O2 / M+• / 248.0397 / 15.35-15.47 / -2.4
Heptachlor epoxide / C10H5Cl7O / [M + H]+ / 386.8238 / 14.82-14.97 / 4.1
Hexachlorobenzene / C6Cl6 / M+• / 281.8131 / 12.26-12.41 / 2.2
Iprodione / C13H13Cl2N3O3 / [M + H]+ / 330.0412 / 17.01-17.11 / 3.9
Malathion / C10H19O6PS2 / M+• / 331.0439 / 13.99-14.15 / 2.9
Malaoxon / C10H19O7PS / [M + H]+ / 315.0667 / 13.41-13.62 / 0.6
Metalaxyl / C15H21NO4 / [M + H]+ / 280.1549 / 13.61-13.84 / -4.1
Methidathion / C6H11N2O4PS3 / [M + H]+ / 302.9697 / 15.32-15.53 / -4.9
Methoxychlor / C16H15Cl3O2 / [M + H]+ / 345.0216 / 17.21-17.40 / 4.1
Parathion ethyl / C10H14NO5PS / [M + H]+ / 292.0409 / 14.27-14.36 / 2.2
Paraoxon-methyl / C8H10NO6P / [M + H]+ / 248.0324 / 15.34-15.50 / 2.0
Penconazole / C13H15Cl2N3 / [M + H]+ / 284.0721 / 14.70-14.80 / 3.1
Pendimethalin / C13H19N3O4 / M+• / 281.1375 / 18.31-18.42 / 4.2
Piridaben / C19H25Cl2N2O / [M + H]+ / 365.1454 / 18.51-18.60 / 3.7
Pirimicarb / C11H18N4O2 / [M + H]+ / 239.1508 / 13.15-13.31 / -3.3
Pirimicarb desmethyl / C10H16N4O2 / M+• / 224.1273 / 15.19-15.37 / -4.3
Pirimiphos methyl / C11H20N3O3PS / [M + H]+ / 306.1041 / 13.89-13.97 / 3.2
Profenofos / C11H15BrClO3PS / [M + H]+ / 372.9430 / 15.45-15.57 / 4.3
Propachlor / C11H14ClNO / [M + H]+ / 212.0842 / 11.15-11.24 / 1.9
Propargite / C19H26O4S / M+• / 350.1552 / 16.73-16.84 / 4.3
Propiconazole / C15H17Cl2N3O2 / [M + H]+ / 342.0776 / 16.17-16.28 / 3.6
Pyridaben / C19H25ClN2OS / [M + H]+ / 365.1454 / 18.50-18.63 / 4.2
Pyrimethanil / C12H13N3 / [M + H]+ / 200.1188 / 12.92-13.03 / 4.5
Quinoxyfen / C15H8Cl2FNO / [M + H]+ / 308.0045 / 16.46-16.61 / -4.1
Tebuconazole / C16H22ClN3O / [M + H]+ / 308.1530 / 16.69-16.86 / -3.6
Tebufenpyrad / C18H24ClN3O / [M + H]+ / 334.1686 / 17.32-17.42 / 3.4
Tecnazene / C6HCl4NO2 / [M + H]+ / 259.8840 / 11.29-11.47 / 4.5
Tefluthrin / C17H14ClF7O2 / [M + H]+ / 419.0649 / 12.97-13.11 / 4.8
Tetraconazole / C13H11Cl2F4N3O / [M + H]+ / 372.0294 / 14.26-14.38 / 4.7
Tetradifon / C12H6Cl4O2S / [M + H]+ / 354.8921 / 17.52-17.71 / 0.8
Tolclofos methyl / C9H11Cl2O3PS / [M + H]+ / 300.9622 / 13.58-13.76 / 3.3
Tradimefon / C14H16ClN3O2 / [M + H]+ / 294.1009 / 14.27-14.48 / 2.4

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Table 2. Validation parameters of the optimized method.

Pesticide / Concentrationa / Inter-day precisionb / Limit of detection
(LOD, µg/kg) / Limit of quantification
(LOQ, µg/kg) / MRLc
(µg/kg)
10 µg/kg / 50 µg/kg / 150 µg/kg
Acephate / N.Ed (-) / 88 (5) / 88 (11) / 24 / 7 / 50 / 20
Aclonifen / N.E (-) / N.E (-) / 89 (3) / 9 / 25 / 150 / 20
Acrinathrin / 58 (35) / 81 (12) / 77 (5) / 8 / 7 / 50 / 50
Azinphos methyl / N.E (-) / 87 (19) / 115 (1) / 4 / 3 / 50 / 10
Benalaxyl / 27 (33) / 86 (5) / 76 (6) / 4 / 10 / 50 / 50*
Bifenox / 91 (10) / 73 (4) / 75 (7) / 9 / 5 / 10 / 50
Bupirimate / 70 (6) / 120 (7) / 111 (2) / 16 / 1 / 10 / 50
Buprofezin / N.E (-) / 71 (1) / 97 (9) / 23 / 25 / 50 / 50
Chlordane / 181 (30) / 98 (5) / 78 (3) / 1 / 1 / 50 / 50*
Chlorfenson / N.E (-) / 86 (1) / 81 (12) / 8 / 1 / 50 / 50
Chlorfenvinfos / N.E (-) / 88 (6) / 112 (6) / 17 / 3 / 50 / 10
Chlorpyrifos methyl / N.E (-) / 119 (3) / 120 (7) / 10 / 1 / 50 / 50
Chlorthal dimethyl / 48 (31) / 120 (4) / 117 (2) / 9 / 1 / 50 / 10
Cyproconazole / N.E (-) / 70 (4) / 90 (2) / 16 / 7 / 50 / 50
Cyprodinil / N.E (-) / 114 (8) / 120 (10) / 4 / 1 / 50 / 50
Diazinon / N.E (-) / 113 (11) / 104 (6) / 1 / 1 / 50 / 50
Dichlobenil / N.E (-) / 111 (9) / 109 (24) / 4 / 1 / 50 / 50
Dicloran / N.E (-) / 120 (20) / 117 (3) / 8 / 3 / 50 / 10
Dieldrin / 37 (5) / 84 (10) / 103 (2) / 9 / 3 / 50 / 200*
Diethofencarb / N.E (-) / 79 (11) / 105 (6) / 10 / 25 / 50 / 50
Diflufenican / 184 (16) / 98 (5) / 110 (4) / 1 / 1 / 50 / 50
Diniconazole / 42 (39) / 96 (12) / 78 (3) / 16 / 10 / 50 / 50
Disulfoton sulfone / 19 (10) / 85 (1) / 85 (2) / 6 / 25 / 50 / 20*
Endosulfan / 19 (9) / 105 (10) / 84 (4) / 3 / 7 / 50 / 50*
Etridiazole / 98 (30) / 86 (4) / 77 (1) / 6 / 5 / 10 / 50
Fenamiphos / N.E (-) / 78 (8) / 101 (2) / 7 / 3 / 50 / 10*
Fenoxycarb / 25 (7) / 76 (7) / 84 (5) / 1 / 3 / 50 / 50
Fenthion / N.E (-) / 76 (3) / 120 (19) / 20 / 10 / 50 / 50*
Fenthion sulfoxide / N.E (-) / 90 (5) / 108 (4) / 2 / 5 / 50 / 50*
Fipronil / 94 (3) / 89 (7) / 70 (11) / 9 / 1 / 10 / 10*
Fluazifop-P-butyl / 22 (9) / 108 (2) / 97 (3) / 4 / 5 / 50 / 50*
Fludioxonil / N.E (-) / 80 (2) / 98 (3) / 7 / 7 / 50 / 50
Hexachlorobenzene / N.E (-) / 86 (4) / 120 (1) / 7 / 10 / 50 / 200
Malaoxon / N.E (-) / 24 (6) / 103 (2) / 16 / 10 / 150 / 20*
Metalaxyl / N.E (-) / N.E (3) / 85 (6) / 4 / 25 / 150 / 50*
Methidathion / N.E (-) / 88 (4) / 83 (3) / 3 / 1 / 50 / 20
Methoxychlor / N.E (-) / 118 (18) / 103 (6) / 5 / 50 / 50 / 10
Paraoxon-methyl / N.E (-) / 71 (6) / 90 (5) / 9 / 10 / 50 / 20*
Pirimicarb / N.E (-) / N.E (-) / 120 (8) / 11 / 25 / 150 / 50*
Pirimicarb desmethyl / 74 (5) / 82 (14) / 89 (6) / 4 / 7 / 10 / 50*
Profenofos / 22 (9) / 91 (4) / 104 (5) / 4 / 3 / 50 / 50
Pyridaben / 38 (7) / 50 (6) / 84 (5) / 4 / 1 / 150 / 20
Quinoxyfen / N.E (-) / 77 (8) / 99 (5) / 6 / 3 / 50 / 200
Tebuconazole / 25 (13) / 81 (1) / 92 (3) / 5 / 1 / 50 / 100
Tecnazene / N.E (-) / N.E (12) / 104 (2) / 5 / 25 / 150 / 50
Tefluthrin / N.E (-) / N.E (9) / 105 (1) / 13 / 50 / 150 / 50
Tetraconazole / 57 (8) / 102 (7) / 99 (12) / 7 / 1 / 50 / 500
Tetradifon / 36 (14) / 77 (5) / 91 (5) / 9 / 25 / 50 / 50
Tolclofos methyl / N.E (-) / 112 (4) / 79 (9) / 13 / 1 / 50 / 50
Triadimefon / N.E (-) / 56 (16) / 92 (1) / 11 / 10 / 150 / 100*

a Repeatability values, expressed as relative standard deviation, RSD (n=5)

b RSD values obtained at 50 µg/kg. Samples were analyzed on 5 consecutive days.

c MRL: Maximum residue limit established by EU,Regulation (EC) No 396/2005.* MRL expressed as sum of compounds.

d N. E.: Not Extracted (Recovery < 10%).

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Fig. 1. Spectra of (a) cyproconazole showing the absence of M+• (m/z291.1138)and the presence of the protonated molecular ion [M + H]+(m/z292.1217); and (b) acrinathrin showing the presence of the molecular ion(m/z541.1324) and the absence of the protonated molecular ion.

Fig. 2. Ionization mechanisms proposed for malaoxon with the APCI source.

Fig. 3.Effect of the application of the clean-up in the recovery.

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