(m/z 283.8102), and a data processing system based on ..... Notes: * The recovery of pesticides (0.05 mg/L or mg/kg) from 10 mL of water using DLLME with ...
ISSN 10619348, Journal of Analytical Chemistry, 2013, Vol. 68, No. 10, pp. 912–923. © Pleiades Publishing, Ltd., 2013. Original Russian Text © V.G. Amelin, D.K. Lavrukhin, A.V. Tret’yakov, 2013, published in Zhurnal Analiticheskoi Khimii, 2013, Vol. 68, No. 10, pp. 1007–1019.
ARTICLES
Combination of the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) Method and Dispersive Liquid–Liquid Microextraction in the Identification and Determination of Pesticides from Various Classes in Food Products by Gas–Liquid Chromatography V. G. Amelina, b, D. K. Lavrukhina, b, and A. V. Tret’yakovb a
Federal Center for Animal Health (VNIIZZh), Yur’evets, Vladimir, 600901 Russia b Vladimir State University, ul. Gor’kogo 87, Vladimir, 600000 Russia Received December 22, 2011; in final form, December 5, 2012
Abstract—A procedure for the identification (104 substances) and determination (40 substances) of the active components of combined pesticides from different classes in water, vegetables, fruits, and meat by gas chromatography with massspectrometric and electroncapture detectors was proposed. The pesticides were extracted from the samples of vegetables, fruits, and meat with acetonitrile using the QuEChERS method. The extracts were preconcentrated by a factor of 50–60 and additionally purified by dispersive liquid–liquid microextraction. The pesticides were extracted from water by dispersive liquid–liquid microextraction with hexane (degree of concentration was higher than 100). The limits of detection by the timeofflight detector equaled 0.01–0.02 mg/kg for solid samples and 1–2 μg/L for aqueous solutions. The limits of quantitation for pesticides were 1–2 mg/kg for solid samples and 0.05–0.1 μg/L for solutions. The analysis time was 1–2 h, and the RSD of the results did not exceed 18%. Keywords: pesticides; gas–liquid chromatography; electroncapture detector; timeofflight massspectro metric detector; water, vegetable, fruit, and meat analysis; QuEChERS method; dispersive liquid–liquid microextraction DOI: 10.1134/S1061934813080029
Along with the use of individual pesticides, the mixtures of pesticides from different classes are com monly used in the agriculture. Combined prepara tions, such as Eforia® (λcyhalothrin and thia methoxam), Engeo® 247 SC, Borey (imidacloprid and λcyhalothrin), NurellD (chlorpyrifos and cyper methrin), Dospekh 3 (tebuconazole and imazalil), Titul duo (tebuconazole and propiconazole), Alto (cyproconazole and propiconazole), and Lyufoks (lufenuron and fenoxycarb), are well known [1, 2]. Chromatography–mass spectrometry [3–5], HPLC [6–9], voltammetry [10], enzyme immunoas say [11, 12], capillary electrophoresis [13–17], and gas chromatography [18, 19] are used for the monitoring of pesticide residues in food, agricultural products, and environmental samples. Procedures for the deter mination of individual pesticides or pesticides of the same class were proposed in the cited publications; however, the mutual effects of pesticides occurring in combination were not studied.
The main problem in the determination of pesti cides consists in their extraction from the test material, the removal of coextracted compounds (fats, waxes, lipids, etc.) from the extract, and the preconcentration of the extract because almost all chromatographic methods are insufficiently sensitive. The Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method was proposed for the safe and rapid extraction of pesticides (primarily for fruits, vegetables, cereals, and honey) [20]. In this method, the extract is not preconcentrated; therefore, it is not applied to the determination of pesticides in products with low maximum permissible levels (MPLs). Chro matography–mass spectrometry is a technique used for the subsequent analysis. However, the insufficient cleaning of the extract restricts the application of this sample preparation method to other chromatographic techniques. A unique preconcentration method—dispersive liquid–liquid microextraction (DLLME)—was pro posed in 2006 for the determination of pesticides in
912
COMBINATION OF THE QUICK, EASY, CHEAP, EFFECTIVE, RUGGED, AND SAFE
water, juices, fruits, and tea [21−23]. This method makes it possible to reach high degrees of preconcen tration and extraction of target components; however, it has limited applications to solid test materials. In this work, we evaluated the possibility of combin ing sample preparation according to the QuEChERS method and extract preconcentration (refining) by DLLME for the identification and determination of pesticides from different classes that simultaneously occurred in water, vegetables, fruits, meat, and other food products using gas–liquid chromatography with massspectrometric and electroncapture detectors. EXPERIMENTAL Instrumentation. Chromatography–massspectro metric analysis was carried out on a Micromass® GCT PremierТМ ToF MS system (Waters, Great Britain), which included an Agilent 6890N gas chromatograph, a timeofflight massspectrometric detector with a resolution of 9300 for hexachlorobenzene (m/z 283.8102), and a data processing system based on an of IBM PCAT personal computer. Separation was performed on a quartz capillary column 30 m in length with an inside diameter of 0.32 mm (DB5ms station ary phase film thickness of 0.25 µm). The column temperature was 40–310°С (heating rate, 15 K/min), and the injector temperature was 240°С. Helium was a carrier gas; the carriergas inlet pressure and flow rate were 0.1 MPa and 1 mL/min, respectively. A 1µL sample was injected into the chromatograph in the splitless mode using a CTC CombiPal autosampler. The mass spectra were measured using 70eV electron ionization; the rate of scanning was 0.09 s, the range of scanning was 40–400 m/z, and the determination error was 0.65 mDa. A Clarus600 gas chromatograph with an electron capture detector (ECD) (PerkinElmer, the United States) was used. Separation was performed on an RtxPesticides® quartz capillary column (Merck, Germany) 30 m in length with an inside diameter of 0.32 mm (stationary phase film thickness of 0.25 µm). The column temperature was 120–310°С (heating rate, 15 K/min), the injector temperature was 240°С, and the detector temperature was 300°С. Nitrogen was a carrier gas, and its flow rate was 2 mL/min. A 1µL sample was injected into the chro matograph in the splitless mode using an autosampler. Reagents. The following standard reference sam ples of individual pesticides (98.5–99% purity) were used: simazine (GSO 771999), atrazine (GSO 7645 99), linuron (GSO 771299), malathion (IPO 460), chlorpyrifos (GSO 741897), bentazon (IPO 050), imi dacloprid (IPO 297), acetamiprid (No. C 10013000, JOURNAL OF ANALYTICAL CHEMISTRY
Vol. 68
913
Dr. Ehrenstorfer), metsulfuron methyl (GSO 8626 2004), propiconazole (IPO 581), tebuconazole (GSO 766999), thiabendazole (RM, No. 45684), thiamethoxam (RM, No. 37924), propazin (GSO 771699), promethrine (GSO 766799), desm etryn (GSO 749898), terbutylazine (SOP 2005), ter butryn (SOP 2105), metribuzin (GSO 771399), metazachlor (IPO 471), metolachlor (SOP 3906), bensulfuron methyl (SOP 6006), sulfometuron methyl (SOP 5506), tribenuron methyl (GSO 8628 2004), diuron (GSO 770399), fluometuron (GSO 772799), chlorbromuron (SOP 2405), ami dosulfuron (SOP 3106), chlortoluron (GSO 7731 99), metoxuron (SOP 1605), triasulfuron (SOP 46 06), penkonazole (GSO 766499), flutriafol (SOP 41 06), cyproconazole (GSO 767799), triticonazole (SOP 6706), triadimefon (GSO 751198), epoxicon azole (GSO 86302004), diniconazole (GSO 7654 99), diphenoconazole (GSO 765699), imazalil (SOP 4006), prochloraz (GSO 771899), thiabenda zole (GSO 772099), carbofuran (GSO 771099), fenoxycarb (SOP 2205), carbosulfan (SOP 4206), dimethoate (IPO 146), fozalon (GSO 741697), par athion methyl (MSO 11332005), pirimiphosmethyl (No. 16270000, Dr. Ehrenstorfer), diazinon (IPO 128), hymexazol (SOP 1305), vinclozolin (SOP 505), and carbaryl (GSO 770999). Pesticide mixture Nos. 34, 36, 40, 44, 51, 118, 128, 129, 232, and 235 (Dr. Ehrenstorfer) were also used. Solutions with a concentration of 100 µg/mL were prepared by the dissolution of the corresponding weighed portions in hexane or acetonitrile. Working solutions were pre pared by diluting the stock solutions with acetonitrile or hexane the day they were used. Acetonitrile, hexane for chromatography, tetra chloromethane, bromobenzene, and dichlo romethane (Merck, Germany); chemically pure MgSO4; chemically pure NaCl; chemically pure sodium citrate tribasic dihydrate; chemically pure sodium citrate dibasic sesquihydrate; and the sorbents BondesilPSA and С18 (Varian, the United States) were used. Sample preparation. The extraction of pesticides from solid samples and the purification of extracts were accomplished using the QuEChERS method. A ground sample of 10 g was placed in a 50mL centri fuge tube, and 10.0 mL of acetonitrile was added; the tube was stoppered, and the contents were vigorously stirred for 1 min. Then, 4.0 g of anhydrous MgSO4, 1.0 g of NaCl, 1.0 g of sodium citrate tribasic dihy drate, and 0.5 g of sodium citrate dibasic sesquihydrate were introduced. After the introduction of the salts, the contents were stirred for 1 min and centrifuged at 3000 rpm for 5 min; an 8mL portion of the upper part No. 10
2013
914
AMELIN et al. 12.87
15.38
βHCCH
2, 4DDE 13.01
12.52
γHCCH
αHCCH
4, 4DDE 15.80
219.0008
246.0907
Time, min Fig. 1. Mass chromatograms of substances with the same fragment masses.
of the extract was taken and transferred to a 15mL centrifuge tube, which contained a mixture of MgSO4 (0.5 g) and the BondesilPSA sorbent (0.5 g) for vege tables and fruits or the С18 sorbent (0.5 g) for meat. The tube was vigorously stirred for 30 s and centrifuged at 3000 rpm for 5 min.
10 mL; 1 mL of acetone containing 100 µL of hexane or chloroform was introduced using a syringe. The resulting emulsion was centrifuged at 3000 rpm for 5 min. The upper layer of hexane (80 ± 3 µL) or chlo roform (40 ± 1 µL) was taken, placed in a microvial, and chromatographed.
In the first version, 4 mL of the extract was taken and evaporated to dryness on a rotary evaporator at a temperature of 40°С. The dry residue was dissolved in 0.4 mL of hexane, and the solution was chromato graphed. In the second version, 4 mL of the extract was placed in a centrifuge tube and diluted with water to
Pesticides were extracted from water using DLLME by the addition of 1 mL of ethanol contain ing 100 µL of hexane (50 µL of chloroform) to 10 mL of water. The resulting emulsion was centrifuged at 3000 rpm for 5 min. The upper layer of hexane (80 ±
transNonachlor
Endosulfan 240.9792
236.9332 195.0098
Pyrene
242.9889
207.0394
228.9820 264.9701 268.9864 262.9597
270.9920 338.9906 276.9769
209.0179
278.9771 340.9861
244.9939 226.9807
Chlordane
337.0010 280.9844
306.9992 308.9942
372.9643 322.9965
370.9499
294.9922 215.9760
245.9928
324.9897
342.9951
376.9605
310.9807
190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 370 380 m/z Fig. 2. Mass spectrum of pyrene, αchlordane, αendosulfan, and transnonachlor at a retention time of 15.58 min. JOURNAL OF ANALYTICAL CHEMISTRY
Vol. 68
No. 10
2013
COMBINATION OF THE QUICK, EASY, CHEAP, EFFECTIVE, RUGGED, AND SAFE
915
Table 1. Pesticides identified by gas chromatography–mass spectrometry (timeofflight massspectrometric detector) Characteristic ions, m/z
tR, min
ion
ion 1
ion 2
Recovery*, %
Chlortoluron Dichlorvos Carbofuran phenol Metribuzin Carbaryl1 Nifos Propachlor DNOC 2,4D methyl ester
8.45 8.46 9.02 9.97 10.98 11.33 11.75 11.85 11.96
132.0450 109.0097 149.0646 198.3448 144.1121 206.9743 176.1041 168.0329 199.0083
167.0285 78.9902 121.0625 141.2064 115.1003 178.9432 120.0880 198.0391 233.9940
104.0443 184.9803 164.0925 – 116.1106 235.0207 77.0357 121.0347 –
83(79) 92(87) 98(94) 89(75) 90(85) 93(89) 99(92) 87(86) 90(93)
Dicamba Trifluralin 2,4D ethyl ester
12.06 12.13 12.48
173.9618 264.0233 146.9721
174.9758 306.0901 110.9883
201.9778 206.0219 184.9974
78(77) 89(88) 91(90)
αHCCH Hexachlorobenzene 2,4D isopropyl ester
12.54 12.59 12.66
219.0008 283.9652 43.0663
181.0019 285.9621 174.9870
217.0004 – 184.9880
93(90) 99(98) 89(83)
Dimethoate Carbofuran Simazine Atrazine Propazine βHCCH Clomazone Dimethipin Pentachloronitrobenzene γHCCH Terbuthylazine Diazinon 2,4D propyl ester
12.73 12.76 12.78 12.83 12.87 12.87 12.90 12.91 12.97 13.03 13.04 13.11 13.15
87.0219 164.0979 201.1608 200.1507 172.0311 219.0008 125.0126 54.0474 236.8505 219.0008 214.0950 179.1226 184.3803
93.0190 149.0656 186.1333 215.1936 214.0950 181.0019 204.1059 39.0206 264.8417 181.0019 173.0504 137.0807 43.0553
229.0274 131.0540 173.1044 – 104.0058 217.0004 205.1080 118.0128 238.8429 217.0004 138.0751 304.1336 174.9815
89(88) 76(70) 75(76) 78(76) 75(73) 90(88) 73(70) 70(69) 93(93) 97(93) 76(73) 76(70) 77(70)
Chlorothalonil 2,4D isobutyl ester
13.25 13.55
265.8941 57.0705
263.9006 319.9891
367.8882 184.9817
89(80) 83(80)
Vinclozolin Desmatryn Dimethenamid Metribuzin 2,4D butyl ester
13.53 13.71 13.74 13.81 13.85
178.0354 213.1053 154.0939 198.0776 184.9917
212.0011 171.0464 230.0828 198.1100 57.0708
123.3802 82.0329 203.0580 82.0670 41.0400
87(89) 78(77) 70(69) 75(77) 89(80)
Metalaxyl Carbaryl2 Prometryn Heptachlor Terbutryn Pirimiphosmethyl Ethofumesate Linuron Malathion Dichlofluanid Chlorpyrifos Triadimefon Aldrin Chlorthaldimethyl Bentazone
13.99 13.99 14.06 14.08 14.20 14.20 14.27 14.32 14.32 14.34 14.43 14.52 14.58 14.61 14.70
160.1033 144.1121 184.0672 271.9655 185.0773 233.0058 161.0546 61.0768 125.0305 123.0087 199.0011 57.0724 262.9194 300.9090 198.0959
130.0763 115.1003 241.1498 100.0605 170.0557 276.0785 207.1190 248.1121 173.1467 167.0524 314.0948 208.0978 260.9236 272.8886 119.0853
206.1305 116.1106 58.0872 273.9663 223.1266 290.0952 105.0709 160.0276 93.0428 223.9463 288.0379 181.0247 264.9160 331.9167 161.1283
87(81) 90(85) 79(78) 95(90) 76(74) 98(87) 87(86) 76(77) 93(90) 76(70) 105(98) 78(70) 99(90) 79(76) 91(90)
Pesticide
JOURNAL OF ANALYTICAL CHEMISTRY
Vol. 68
No. 10
2013
Chemical class Phenylureas OPP** Carbaminates symTriazines Carbaminates OCP OCP*** 2,6Dinitroocresol Arylhydroxyalkyl carboxy lic acid esters Benzoic acid derivatives Dinitroanilines Arylhydroxyalkyl carboxy lic acid esters OCP OCP Arylhydroxyalkyl carboxy lic acid esters OPP Carbaminates symTriazines symTriazines symTriazines OCP Isoxyzolidinones OCP OCP Triazines OPP Arylhydroxyalkyl carboxy lic acid esters OCP Arylhydroxyalkyl carboxy lic acid esters Dinitroanilines symTriazines Amides symTriazines Arylhydroxyalkyl carboxy lic acid esters Alanine derivatives Carbaminates symTriazines OCP symTriazines OPP Benzofurans Phenylureas OPP Sulfinamides OPP OPP OCP OCP Thiadiazines
916
AMELIN et al.
Table 1. (Contd.)
Pendimethalin Metazachlor Penconazole Isophen Heptachlor epoxide Procymidone Triadimenol Captan γChlordane Fluometuron 2,4DDE αChlordane αEndosulfan transNonachlor Imazalil Oxadiazon Oxyfluorfen 4,4DDE Buprofezin 2,4D ethylhexyl ester
14.90 14.94 15.01 15.04 15.07 15.15 15.18 15.22 15.38 15.20 15.40 15.57 15.58 15.58 15.67 15.78 15.81 15.83 15.88 15.88
Characteristic ions, m/z ion ion 1 ion2 252.1172 162.0730 208.0686 81.0517 133.0978 209.0613 159.0061 248.1495 161.0064 211.0350 163.0164 205.0498 353.0176 355.0221 351.0188 96.0569 255.0228 285.0151 112.0988 168.1254 128.0083 79.0552 149.0438 262.9597 372.9163 374.9684 – 202.1322 200.1215 203.1413 246.0907 248.0885 – 372.9163 374.9684 – 240.9921 236.9266 238.8498 236.9459 243.0083 – 172.9512 174.9428 158.9643 258.0325 174.9538 – 252.0323 280.0176 318.0418 246.0907 248.0885 – 105.0524 106.0565 83.0543 219.9653 221.9669 57.0705
2,4DDD Dieldrin Nitrofen Endrin βEndosulfan Fluazinam 4,4DDD 2,4DDT Propiconazole1 Propiconazole2 4,4DDT 2,4Methoxychlor Dichlorofopmethyl
15.90 15.93 16.13 16.21 16.34 16.37 16.37 16.41 16.72 16.79 16.85 16.90 17.08
235.1088 262.9996 283.0965 317.0298 241.0051 386.9798 235.0268 235.1088 69.0724 69.0724 235.0332 121.0716 252.9650
237.0374 265.0630 285.0630 281.0474 236.9330 358.9639 237.0374 237.1198 172.9675 172.9675 237.0374 227.1140 254.9637
– – 253.0826 245.0396 238.3388 – – – 259.0508 259.0508 – 346.0333 340.0208
89(78) 96(90) 79(77) 87(88) 90(89) 75(80) 90(93) 89(90) 78(77) 80(81) 93(90) 87(80) 86(87)
Bifenthrin Fenoxycarb Bromopropylate 4,4Methoxychlor Phosalone Amitraz γCyhalothrin Mirex FenoxapropPethyl cisPermethrin transPermethrin Pyridaben Prochloraz βCyfluthrin αCypermethrin β Cypermethrin Fluvalinate Esfenvalerate Difenoconazole1 Difenoconazole2 Deltamethrin
17.39 17.48 17.49 17.53 17.88 18.05 18.05 18.26 18.44 18.51 18.71 18.75 18.79 19.10 19.21 19.31 20.01 20.08 20.29 20.36 20.57
181.0878 88.0349 340.9259 227.1208 182.0143 132.0648 181.0704 271.9521 288.0327 183.0968 183.0968 147.1196 70.0311 206.0701 181.0761 181.0761 250.0789 125.0218 265.0118 265.0118 181.0761
166.0663 116.0751 182.9549 184.0974 121.0466 147.0799 141.0528 273.9479 182.0540 127.0230 127.0230 119.0769 180.1190 127.0278 127.0278 127.0278 181.0704 181.0760 267.0022 267.0022 252.8237
141.0382 186.0714 – 228.1207 111.0025 162.1001 197.0428 269.9360 361.0974 155.0851 155.0851 309.0734 285.9644 199.0557 163.0195 163.0195 252.0779 225.0740 323.0879 323.0879 171.9760
98(99) 86(88) 79(78) 87(80) 83(79) 78(70) 95(106) 93(96) 76(80) 89(87) 89(87) 69(70) 77(75) 93(103) 98(89) 98(89) 80(91) 93(103) 87(88) 87(88) 98(99)
Pesticide
tR, min
Recovery*, % 77(78) 75(75) 75(79) 69(70) 91(89) 76(73) 78(76) 98(97) 97(98) 75(71) 90(85) 99(93) 87(86) 90(85) 76(77) 73(75) 70(73) 92(93) 98(97) 87(88)
Chemical class Phenylamines Phenylamines Triazoles OPP OCP Dicarboxylic acid imides Triazoles Phthalimines OCP Phenylureas OCP OCP OCP OCP Imidazoles Oxadiazones Diphenyl ethers OCP Thiadiazines Arylhydroxyalkyl carboxy lic acid esters OCP OCP Phenyl ethers OCP OCP Pyrimidine amines OCP OCP Triazoles Triazoles OCP OCP Arylhydroxyphenoxy pro pionates Pyrethroids Carbaminates Benzylates OCP OPP Amidines Pyrethroids OCP OPP Pyrethroids Pyrethroids Pyridazinones Azoles Pyrethroids Pyrethroids Pyrethroids Pyrethroids Pyrethroids Triazoles Triazoles Pyrethroids
Notes: * The recovery of pesticides (0.05 mg/L or mg/kg) from 10 mL of water using DLLME with hexane and (in parentheses) from 10 mL of an aqueous solution containing 4 mL of an acetonitrile extract from grapes using the QuEChERS method. ** OPP refers to organophosphorus pesticides. *** OCP refers to organochlorine pesticides. JOURNAL OF ANALYTICAL CHEMISTRY
Vol. 68
No. 10
2013
COMBINATION OF THE QUICK, EASY, CHEAP, EFFECTIVE, RUGGED, AND SAFE
917
Table 2. Pesticide recovery with the use of DLLME (matrix: water of a meat extract obtained in accordance with the QuEChERS method) Recovery, % Pesticide chloroform (50–40 μL)
hexane (100–80 μL)
dichloromethane (200–30 μL)
bromobenzene (30–20 μL)
tetrachloromethane (50–40 μL)
Chlorpyrifos
98 ± 5
103 ± 3
65 ± 4
30 ± 6
63 ± 4
Bifenthrin
99 ± 2
110 ± 8
66 ± 5
54 ± 7
58 ± 5
λCyhalothrin
87 ± 3
92 ± 5
56 ± 4
65 ± 4
65 ± 4
Cypermethrin
97 ± 3
99 ± 4
58 ± 5
30 ± 3
37 ± 6
105 ± 12
88 ± 2
67 ± 8
72 ± 2
45 ± 7
Fluvalinate
Note: Extractant added and the resulting phase volumes, respectively.
(а)
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time, min (b)
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time, min
Fig. 3. Chromatograms of extracts from grape prepared by the QuEChERS method (a) with extract evaporation in accordance with the first version and (b) in combination with DLLME (extractant: hexane). JOURNAL OF ANALYTICAL CHEMISTRY
Vol. 68
No. 10
2013
918
AMELIN et al. (а)
1
2
3
5
4 2
4
6
8
10
12
14
16
18
20
22 24 Time, min
(b)
1 3
2
4 2
4
6
8
10
12
14
16
18
20
5
22 24 Time, min
(c)
1
3
5
2 4 2
4
6
8
10
12
14
16
18
20
22 24 Time, min
Fig. 4. Chromatograms of microextracts from grape prepared with the use of (a) hexane, (b) chloroform, (c) bromobenzene, (d) dichloromethane, (e) tetrachloromethane, and (f) a standard mixture: (1) chlorpyrifos, (2) bifenthrin, (3) λcyhalothrin, (4) cypermethrin, and (5) fluvalinate. JOURNAL OF ANALYTICAL CHEMISTRY
Vol. 68
No. 10
2013
COMBINATION OF THE QUICK, EASY, CHEAP, EFFECTIVE, RUGGED, AND SAFE (d)
1 2 2
4
6
8
10
12
14
16
5
4
3 18
20
22 24 Time, min
(e)
1 2 2
4
6
8
10
12
14
1
16
4
3 18
20
5
22 24 Time, min
(f)
3
2 5 4
2
4
6
8
10
12
14
16
Fig. 4. Contd. JOURNAL OF ANALYTICAL CHEMISTRY
Vol. 68
No. 10
2013
18
20
22 24 Time, min
919
920
AMELIN et al.
Table 3. Pesticides determined by GCECD, calibration equations, and analytical ranges Pesticide Linuron Dichlorvos
tR, min
Analytical range, mg/L
4.97
0.1–10
Y = 1627x – 37x2
0.1–10
2
5.06
Chlorbromuron
5.87
0.1–10
Hexachlorobenzene
8.78
0.005–0.1
αHCCH
9.28
0.01–0.1
Propachlor
R2
Calibration equation
Y = 558x + 674x
Y = –839 + 20871x – 47x
0.9893 0.9985 2
0.9998
Y = 231.374x
0.9958
Y = 54694x
9.47
0.1–10
γHCCH
10.07
0.01–0.1
Y = 52465x
βHCCH
10.29
0.01–0.1
Y = 38550x
0.9980
Y = 221x + 64x
2
0.9992 0.9981 0.9977
2
Diazinon
10.44
0.1–10
Heptachlor
11.1
0.01–0.1
Y = 51993x
0.9975
Dimethoate
11.38
0.01–0.1
Y = 41895x
0.9987
Aldrin
11.81
0.01–0.1
Y = 62516x
0.9981
Chlorothalonil
12.04
0.01–0.1
Y = 16914x
Chlorpyrifos
12.64
0.1–10
Vinclozolin
12.81
0.1–10
Malathion
13.05
0.005–0.1
Y = 153x – 73x
0.9989
0.9988
Y = 12953x –
333x2
0.9996
Y = 22736x –
518x2
0.9981
Y = 13057x
0.9992 689x2
Dichlofluanid
13.26
0.1–10
Y = 129x –
2,4DDE
13.31
0.01–0.1
Y = 57781x
0.9962
Triadimefon
13.64
0.1–10
Y = (53.254044)x + (13.154065)x2
0.9985
4,4DDE
13.99
0.01–0.1
Y = 138539x
0.9972
Penconazole Thiamethoxam
14.04 14.15
0.1–10 0.1–10
0.9998
Y = 9188x +
23x2
0.9987
Y = 2221x +
83x2
0.9983
135x2
0.9989
Captan
14.20
0.1–10
Y = 5382x +
2,4DDD
14.31
0.01–0.1
Y = 48790x
0.9947
Dieldrin
14.51
0.01–0.1
Y = 57225x
0.9960
2,4DDT
14.87
0.01–0.1
Y = 15813x
0.9961
Endrin
14.99
0.01–0.1
Y = 49621x
0.9950
4,4DDD
15.17
0.01–0.1
Y = 52983x
0.9970
Imazalil
15.28
0.005–0.1
Y = 39685x
0.9441
βEndosulfan
15.45
0.01–0.1
Y = 55853x
0.9944
4,4DDT
15.78
0.01–0.1
Y = 9366x
0.9950
Propiconazole1
16.55
0.005–0.1
Y = 10197x
0.9931
Propiconazole2
16.72
0.005–0.1
Y = 18701x
Bifenthrin
17.13
0.1–10
Y = 582x +
Chloridazon
17.28
0.005–0.1
Y = 39073x
Phosalone
18.77
0.1–10
γCyhalothrin
19.27
0.005–0.1
Y = 84203x
Cypermethrin
20.74
0.005–0.1
Y = 7880x
0.9947 15x2
0.9998
Y = 35x + 364x
Esfenvalerate
21.64
0.1–10
Y = 472x +
Fluvalinate
22.32
0.005–0.1
Y = 16542x
0.9995
2
0.9984 0.9973 0.9997
48x2
JOURNAL OF ANALYTICAL CHEMISTRY
0.9995 0.9975 Vol. 68
No. 10
2013
COMBINATION OF THE QUICK, EASY, CHEAP, EFFECTIVE, RUGGED, AND SAFE
921
Table 4. Results of the analysis of food products (n = 3; P = 0.95)
Test material
Pesticide detectedl
Found, mg/kg
sr
MPL*, mg/kg
0.010 ± 0.003 0.76 ± 0.06
0.18 0.05
0.05 0.1
Banana
Triadimefon Imazalil
Canned corn
Vinclozolin Triadimefon Thiamethoxam
0.0011 ± 0.0003 0.070 ± 0.003 0.022 ± 0.002
0.16 0.03 0.03
0.1 0.05 0.1
Peach
Chlorpyrifos Vinclozolin Triadimefon Penconazole Thiamethoxam
0.0020 ± 0.0003 0.075 ± 0.004 0.10 ± 0.01 0.042 ± 0.003 0.041 ± 0.002
0.09 0.03 0.06 0.04 0.03
0.005 1.0 0.05 0.3 0.1
Strawberry
Chlorbromuron Chlorpyrifos Thiamethoxam Vinclozolin Triadimefon Penconazole
0.050 ± 0.002 0.0032 ± 0.0005 0.21 ± 0.03 0.0042 ± 0.0008 0.22 ± 0.02 0.13 ± 0.03
0.03 0.10 0.09 0.11 0.05 0.14
0.05 0.005 0.1 Not allowed Not allowed 0.1
Cabbage
Chlorpyrifos
0.81 ± 0.05
0.04
0.01
Natural water
Hexachlorobenzene αHCCH 2,4DDT 4,4DDE Atrazin
0.13
0.002 0.002 0.1 0.1 0.002
0.0001 0.0001 0.0002 0.0004 0.0041 ± 0.0002
* Maximum permissible levels of pesticide residues in the fresh food products of plant origin regulated by Russian legislation in accor dance with GN 1.2.132303 (with addenda 1–9).
JOURNAL OF ANALYTICAL CHEMISTRY
Vol. 68
No. 10
2013
922
AMELIN et al.
Table 5. Pesticide recoveries and the results of the determination of pesticides in meat (n = 3; P = 0.95). The recovery was determined upon the addition of 0.05 mg/kg of pesticide Meat beef
Pesticide
Linuron Dichlorvos Chlorbromuron Propachlor Diazinon Chlorothalonil Chlorpyrifos Vinclozolin Malathion Dichlofluanid Triadimefon Penconazole Thiamethoxam Captan Imazalil Diniconazole Propiconazole Bifenthrin Chloridazon Phosalone λCyhalothrin Fluvalinate αCypermethrin βCypermethrin Esfenvalerate
pork
chicken
found, mg/kg
recovery, %
found, mg/kg
recovery, %
found, mg/kg
recovery, %
– – – – – – 0.021 ± 0.006 – – – 0.22 ± 0.03 – – – – – – – – – – – – 0.53 ± 0.06 –
85 78 87 65 75 89 69 67 89 75 83 78 89 76 98 87 80 69 93 88 72 75 63 52 68
– – – – – – 0.0070 ± 0.0006 – – – 0.002 ± 0.003 – – – – – – – – – – – – – –
77 80 90 66 70 80 61 73 85 70 85 76 67 65 96 80 85 75 73 69 70 70 60 66 68
– – – – – – 0.033 ± 0.006 – – – 0.12 ± 0.03 – – – – – – – – – – – – 0.38 ± 0.03 –
90 79 95 69 68 80 71 75 89 88 100 89 76 87 100 88 92 73 71 76 88 75 70 65 70
* Not detected.
2 µL or 40 ± 1 µL of chloroform) was taken, placed in a microvial, and chromatographed. RESULTS AND DISCUSSION Identification of pesticides. Polar pesticides are well separated on a capillary column with the stationary phase DB5ms and determined using a timeofflight massspectrometric detector. The isomers of synthetic pyrethroids, propiconazole, diphenoconazole, car baryl, HCCH, DDE, and DDT have the same masses of characteristic ions but different retention times (Table 1, Fig. 1). Figure 2 shows the massspectra of αchlordane, αendosulfan and transnonachlor, which form a single peak (15.58 min) in the total ion
current chromatogram. The use of the ChromaLynxТМ software makes it possible to identify these compounds in the selective ion monitoring mode. The limits of detection were 0.5–1 mg/L for 104 pesticides; therefore, for the identification of pes ticides with consideration for their MPLs in the ana lyzed materials, the extracts from solid test materials obtained according to the QuEChERS method were preconcentrated by a factor of 50, and water was pre concentrated by a factor of 100–200 with the use of DLLME. As an example, Table 1 summarizes the recoveries of pesticides from water and the extracts from grapes; these values are higher than 70%. Optimization of DLLME conditions. Chloroform, dichloromethane, tetrachloromethane, bromoben
JOURNAL OF ANALYTICAL CHEMISTRY
Vol. 68
No. 10
2013
COMBINATION OF THE QUICK, EASY, CHEAP, EFFECTIVE, RUGGED, AND SAFE
zene, and hexane were used as extractants for DLLME, and ethanol, acetone, and methanol were used as dispersants. Hexane and chloroform dissolved in ethanol were the best systems because cleaner extracts were obtained with their use, and the degree of pesticide extraction was higher than 80% (Table 2 and Figs. 3, 4). In this case, chlorpyrifos and synthetic pyrethroids were chosen as model pesticides because they are commonly used. Determination of pesticides by GCECD. The majority of pesticides contain chlorine, chlorine and fluorine, chlorine and bromine, or sulfur atoms as constituents; therefore, an ECD, which is more sensi tive, was used for quantitative analysis. All of the pyre throids other than deltamethrin and bifenthrin are the mixtures of isomers, and they appear in chromato grams as two (cyhalothrin, cyfluthrin, permethrin), three (esfenvalerate) and four (cypermethrin) peaks. The limits of detection of pesticides (signal/noise ratio = 3) were 0.05–0.1 mg/kg; therefore, a precon centration factor of 10 is sufficient for their determina tion in vegetables, fruits, and meat (Table 3). We developed a procedure for the quantitative determination of 40 pesticides in water, vegetables, fruits, and meat in the concentration range of 1– 100 µg/kg or 0.05–100 µg/L for water (Tables 4, 5). We found that the concentrations of pesticide residues were higher than the MPLs of imazalil, triadimefon, thiamethoxam, penconazole, and vinclozolin in vege tables and fruits and of chlorpyrifos, cypermethrin, and triadimefon in beef and chicken meat. The dura tion of analysis was 1–2 h, and the relative standard deviation of the results of analysis was no higher than 18%. REFERENCES 1. Mel’nikov, N.N., Novozhilov, P.K., Belan, S.R., and Pylova, T.N., Spravochnik po pestitsidam (Handbook of Pesticides), Moscow: Khimiya, 1985. 2. Mel’nikov, N.N., Pestitsidy. Khimiya, tekhnologiya i primenenie (Pesticides: Chemistry, Technology, and Use), Moscow: Khimiya, 1987. 3. Navalon, A., Gonzalez Casado, A., ElKhattabi, R., and Vilchez, J.L., Analyst, 1997, vol. 122, p. 579. 4. Petrova, T.M., Smirnova, I.M., and Volgarev, S.A., Agrokhimiya, 2006, no. 4, p. 84.
JOURNAL OF ANALYTICAL CHEMISTRY
Vol. 68
923
5. Barinova, E.S., Brodskii, E.S., Koverzanova, E.V., and Usachev, S.V., Zh. Anal. Khim., 1995, vol. 50, no. 3, p. 323. 6. Koverzanova, E.V., Barinova, E.S., and Brodskii, E.S., J. Anal. Chem., 1996, vol. 51, no. 4, p. 397. 7. GuandGuo, Y. and Rai, S.K., J. Environ. Sci. Health, Part B: Pestic., Food Contam., Agric. Wastes, 2004, vol. 39, p. 737. 8. Mandich, A.I., Lazich, S.D., Okresh, S.N., and Gaal, F.F., Zh. Anal. Khim., 2005, vol. 60, no. 12, p. 1273. 9. Rancan, M., Sabatini, A.G., Achilli, G., and Galletti, G.C., Anal. Chim. Acta, 2006, vol. 555, p. 20. 10. Navalon, A., ElKhattabi, R., and Gonzalez Casado, A., Microchim. Acta, 1999, vol. 130, p. 261. 11. Wanatabe, S., Ito, S., Kamata, Y., Omoda, N., Yamazaki, T., Munakata, H., Kaneko, T., and Yuasa, Y., Anal. Chim. Acta, 2001, vol. 427, p. 211. 12. Eiki, W., Heesoo, E., Koji, B., Tomohito, A., Yasuo, I., Shozo, E., and Masako, U., Anal. Chim. Acta, 2004, vol. 521, p. 45. 13. Carretero, A., CrucesBlanco, C.,Perez Duran, S., and Fernandez Gutierrez, A., J. Chromatogr., A, 2003, vol. 1003, p. 189. 14. Dinelli, G., Bonetti, A., Catizone, P., and Galletti, G.C., J. Chromatogr., B, 1994, vol. 656, p. 275. 15. Hinsman, P., Arce, L., Rios, A., and Valcarcel, M., J. Chromatogr., A, 2000, vol. 866, p. 137. 16. Bolygo, E. and Atreya, N.C., Fresenius’ J. Anal. Chem., 1991, vol. 339, p. 423. 17. Ibrahim, W., Aini, W., Monjurul, AlamS.M., and Sulaiman, A., J. Teknologi, C 2003, vol. 38, p. 51. 18. Niewiadowska, A., Kiljanek, T., Semeniuk, S., and Zmudzki, J., Bull. Vet. Inst. Pulawy, 2010, vol. 54, p. 595. 19. You, J., Weston, D.P., and Lydy, M.J., Arch. Environ. Contam. Toxicol., 2004, vol. 47, p. 141. 20. Anastassiades, M., Stajnbaher, D., and Schenck, F.J., J. AOAC Int., 2003, vol. 86, no. 2, p. 412. 21. Zang, X.H., Wu, Q.H., Zhang, M.Y., Xi, G.H., and Wang, Z., Chin. J. Anal. Chem., 2009, vol. 37, p. 161. 22. Asensio Ramos, M., Ravelo Perez, L.M., Gonzalez Curbelo, M.A., and Hemandez Borges, J., J. Chro matogr., A, 2011, vol. 1218, p. 7415. 23. Krylov, V.A., Krylov, A.V., Mosyagin, P.V., and Mat kivskaya, Yu.O., J. Anal. Chem., 2011, vol. 66, no. 4, p. 331. Translated by V. Makhlyarchuk
No. 10
2013
