Multi-residue Method for Agricultural Chemicals by GC-MS (Animal and Fishery Products)

Transcription

1 Multi-residue Method for Agricultural Chemicals by GC-MS (Animal and Fishery Products) 1. Analytes For muscle, fat, liver, kidney and fish/shellfish, see Table 5. For milk, egg and honey, see Table Instrument Gas chromatograph/mass spectrometer (GC-MS) 3. Reagents Use the reagents listed in Section 3 of the General Rules, except the following. Reference standards of agricultural chemicals: Reference standards of known purities for each agricultural chemical. 4. Procedure Extraction i) Muscle, fat, liver, kidney and fish/shellfish For muscle, liver, kidney and fish/shellfish, weigh 20.0 g of sample. For fat, weigh 5.0 g of sample. Add 20 ml of water to the sample, homogenize, add 100 ml of acetone/n-hexane (1:2, v/v), homogenize again, centrifuge at 2,500 rpm for 5 minutes, and collect the organic layer. Add 50 ml of n-hexane to the residue, homogenize, and centrifuge at 2,500 rpm for 5 minutes. Combine the obtained organic layers, dehydrate with anhydrous sodium sulfate, and filter out the anhydrous sodium sulfate. Concentrate the filtrate at below 40 C, and remove the solvent. Weigh the residue and record the weight as the extracted fat weight. Take all or aliquot of the residue, and dissolve in acetone/cyclohexane (1:4, v/v) so that the amount applying to a gel permeation chromatography column (styrene-divinylbenzene copolymer column) corresponds to 5.0 g of sample. (If the extracted fat weight in 5.0 g of sample is more than 0.5 g, the amount applying to the column should be corresponded to 0.50 g of extracted fat). ii) Milk, egg and honey For milk and egg, weigh 20.0 g of sample. For honey, weigh 20.0 g of sample and dissolve in 20 ml of water. Add 100 ml of acetonitrile, homogenize, centrifuge at 2,500 rpm for 5 minutes, and take the organic layer. Add 50 ml of acetonitrile to the residue, homogenize, and centrifuge at 2,500 rpm for 5 minutes. Combine the obtained organic layers, add 10 g of sodium chloride, and shake. Let stand and discard the separated aqueous layer. Dehydrate the

2 acetonitrile layer with anhydrous sodium sulfate, and filter out the anhydrous sodium sulfate. Concentrate the filtrate at below 40 C and remove the solvent. For milk and egg, dissolve the residue in acetone/cyclohexane (1:4, v/v) so that the amount applying to a gel permeation chromatography column (styrene-divinylbenzene copolymer column) corresponds to 5.0 g of sample. For honey, dissolve the residue in acetone/n-hexane (1:1, v/v) to make exactly 10 ml. Clean-up i) Muscle, fat, fish/shellfish milk, and egg a) Gel permeation chromatography Centrifuge the solution obtained in at 3,000 rpm for 5 minutes, transfer 5 ml of the supernatant to the gel permeation chromatography column (styrene-divinylbenzene copolymer column), and elute with acetone/cyclohexane (1:4, v/v). Collect the fraction eluted from the retention time of acrinathrin to the finish time of tricyclazole elution, concentrate at below 40 C, and remove the solvent. Dissolve the residue in 2 ml of acetone/n-hexane (1:1, v/v). b) Ethylenediamine-N-propylsilanized silica gel column chromatography Add 10 ml of acetone/n-hexane (1:1, v/v) to an ethylenediamine-n-propylsilanized silica gel cartridge (500 mg), and discard the effluent. Transfer the solution obtained in a) to the cartridge, elute with 20 ml of acetone/n-hexane (1:1, v/v), collect the total eluate, concentrate at below 40 C, and remove the solvent. Dissolve the residue in acetone/n-hexane (1:1, v/v) to make exactly 1 ml (0.5 ml for fat), and use this solution as the test solution. ii) Liver and kidney a) Gel permeation chromatography Centrifuge the solution obtained in at 3,000 rpm for 5 minutes, transfer 5 ml of the supernatant to the gel permeation chromatography column (styrene-divinylbenzene copolymer column), and elute with acetone/cyclohexane (1:4, v/v). Collect the fraction eluted from the retention time of acrinathrin to the finish time of acrinathrin elution (Fraction I), and the fraction eluted from the finish time of Fraction I collection to the finish time of tricyclazole elution (Fraction II). b) Ethylenediamine-N-propylsilanized silica gel column chromatography Add 10 ml of acetone/cyclohexane (1:4, v/v) to an ethylenediamine-n-propylsilanized silica gel cartridge (500 mg), and discard the effluent. Transfer the Fraction I to the cartridge, elute with 5 ml of acetone/cyclohexane (1:4, v/v), collect the total eluate, concentrate at below 40 C, and remove the solvent. Dissolve the residue in 1 ml of n-hexane.

3 c) Silica gel column chromatography Add 10 ml of n-hexane to the silica gel cartridge (690 mg), and discard the effluent. Transfer the solution obtained in b) to the cartridge, add 10 ml of n-hexane, and discard the effluent. Elute with 15 ml of diethyl ether/n-hexane (1:19, v/v), combine the eluate with Fraction II obtained in a), concentrate at below 40 C, and remove the solvent. Dissolve the residue in acetone/n-hexane (1:1, v/v) to make exactly 1 ml, and use this solution as the test solution. iii) Honey Add 10 ml of acetone/n-hexane (1:1, v/v) to an ethylenediamine-n-propylsilanized silica gel cartridge (500 mg), and discard the effluent. Transfer 2.5 ml of acetone/n-hexane (1:1, v/v) solution obtained in to the cartridge, elute with 20 ml of acetone/n-hexane (1:1, v/v), collect the total eluate, concentrate at below 40 C, and remove the solvent. Dissolve the residue in acetone/n-hexane (1:1, v/v) to make exactly 1 ml, and use this solution as the test solution. 5. Calibration curve Prepare stock standard solutions (acetone) of each reference standard of agricultural chemical. Mix them, and prepare several solutions (acetone/n-hexane (1:1, v/v)) containing each agricultural chemical at appropriate concentration ranges. Inject 2 µl of each standard solution to GC-MS, and make calibration curves by peak-height or peak-area method. 6. Quantification Inject 2 µl of the test solution to GC-MS, and calculate the concentration of each agricultural chemical from the calibration curves made in Confirmation Confirm using GC-MS. 8. Measurement conditions GC-MS Column: 5% phenyl-methyl silicone, 0.25 mm in inside diameter, 30 m in length and 0.25 µm in film thickness Column temperature: 50 C (1 min) - 25 C/min heating C (0 min) - 10 C/min heating C (10 min) Inlet temperature: 250 C Carrier gas: Helium Ionization mode (voltage): EI (70 ev) Major monitoring ions (m/z): See Table 5 and 6. Expected retention time: See Table 5 and 6.

4 9. Limit of quantification See Table 5 and 6. Note that these tables show examples of limits of measurement (ng), not limits of quantification. 10. Explanatory note Outline of analytical method The method consists of extraction of each agricultural chemical from sample with acetone/n-hexane (1:2, v/v) (acetonitrile for milk, egg and honey), clean-up with a gel permeation chromatography and an ethylenediamine-n-propylsilanized silica gel column chromatography (also clean-up with a silica gel column chromatography for liver and kidney, omit gel permeation chromatography for honey), and quantification and confirmation using GC-MS. Notes i) Table 5 and 6 list the analytes for which this method is applicable in the order they appear in the Japanese syllabary. Note that the maximum residue limits (MRLs) defined for some agricultural chemicals include not only the parent compounds, but also their metabolites or other transformation products, which are inapplicable to this method. Isomers with different retention times are listed as separate Analytes. Degradation product in parentheses means that the analyte is a degraded product which is formed during analysis. ii) This method does not ensure simultaneous analysis of all of the analytes listed in Table 5 and 6. In advance, confirm that degradation or interference does not occur as the result of interaction between the target analytes. iii) Gas chromatograph/tandem mass spectrometer (GC-MS/MS) can also be used for analyses. iv) If the quantity of sodium chloride (10 g) is too large to add to the acetonitrile extract, it may be reduced so long as saturation is achieved. v) Concentration and complete removal of the solvent should be performed under a gentle stream of nitrogen. vi) An example of the conditions for gel permeation chromatography is shown below. Column: Styrene-divinylbenzene copolymer column (20 mm in inside diameter and 300 mm in length) connected with a styrene-divinylbenzene copolymer column (20 mm in inside diameter and 100 mm in length) as a guard column, or other column with equal characteristics. Mobile phase: acetone/cyclohexane (1:4, v/v) Flow rate: 5 ml/min

5 Column temperature: 40 C Injection volume: 5 ml Monitoring wavelength: 254 mm Collection range: Determine in advance using the following method. Prepare 5 mg/l mixed solution of acrinathrin and tricyclazole in mobile phase, transfer 5 ml of the solution to a gel permeation chromatography column, monitor the retention times at 254 nm, and confirm the elution positions. Alternative methods, such as, collecting fractions at appropriate intervals and analyzing by GC-MS(/MS) can also be used. a. Collection range for muscle, fat, fish/shellfish, milk and egg (Figure From the retention time of acrinathrin to the finish time of tricyclazole elution (Example) 58 to 165 ml (total volume: 107 ml) acrinathrin tricyclazole Collection range 58 ml 165 ml Figure 1. Collection range for muscle, fat, fish/shellfish, milk and egg

6 b. Collection range for liver and kidney (Figure Fraction I: From the retention time of acrinathrin to the finish time of its elution Fraction II: From the finish time of Fraction I collection to the finish time of tricyclazole elution (Example) Fraction I: 58 to 65 ml (total volume: 7 ml), Fraction II: 65 to 165 ml (total volume: 100 ml) acrinathrin tricyclazole Fraction II 165 ml Fraction I (58 to 65 ml) Contains high amounts of matrix components. Figure 2. Collection range for liver and kidney vii) Before using cartridges for clean-up, confirm the elution position of each agricultural chemical. viii) For samples containing high quantities of fat, the concentration rates for the test solutions are low. If the targeted measurement sensitivity is not achievable, repeat the gel permeation chromatography procedure, and thereafter, using the extracted fat, combine the solutions and use the new mixture as the test solution. ix) Matrix-matched calibration or standard addition may be required to obtain accurate measurement results. x) Because the limit of quantification differs depending on the instrument used, the concentration rate of the test solution, and the injection volume, it may be necessary to optimize the conditions. 11. References None 12. Type C

7 Table 5. Multi-residue Method for Agricultural Chemicals by GC-MS (Animal and Fishery Products:muscle, fat, liver, kidney and fish/shellfish) Agricultural chemicals Analytes Reten tion index Monitoring ions (m/z) Limit of measur ement (ng) γ-bhc(lindane) γ-bhc(lindane) DDT o,p'-ddt p,p'-ddd p,p'-dde p,p'-ddt EPTC EPTC Azinphos-methyl Azinphos-methyl Atrazine Atrazine Ametryn Ametryn Alachlor Alachlor Aramite Aramite (isomer Aramite (isomer Aramite (isomer 3) Aramite (isomer 4) Aldrin/Dieldrin Aldrin Allethrin Allethrin (isomer 1/isomer Allethrin (isomer 3/isomer 4) Isoprothiolane Isoprothiolane Iprodione Iprodione Iprodione metabolite Imazalil Imazalil Fenvalerate Esfenvalerate (isomer Esfenvalerate (isomer Ethion Ethion Etoxazole Etoxazole Ethofumesate Ethofumesate Ethoprophos Ethoprophos Etridiazole Etridiazole Epoxiconazole Epoxiconazole Endosulfan α-endosulfan β-endosulfan Endosulfan sulfate Endrin Endrin Oxadiazon Oxadiazon Oxabetrinil Oxabetrinil Oxyfluorfen Oxyfluorfen Carfentrazone-ethyl Carfentrazone-ethyl

8 Carboxin Carboxin Carbosulfan Carbosulfan Quinoxyfen Quinoxyfen Quintozene Quintozene Kresoxim-methyl Kresoxim-methyl Chlorthal-dimethyl Chlorthal-dimethyl Chlordane cis-chlordane trans-chlordane Oxychlordane Chlorpyrifos Chlorpyrifos Chlorpyrifos-methyl Chlorpyrifos-methyl Chlorfenapyr Chlorfenapyr Chlorfenson Chlorfenson Chlorfenvinphos (E)-Chlorfenvinphos (Z)-Chlorfenvinphos Chlorbufam Chlorbufam Chlorbenside Chlorbenside Chloroneb Chloroneb Chlorobenzilate Chlorobenzilate Diclofop-methyl Diclofop-methyl ,1-Dichloro-2,2-bis(4-1,1-Dichloro-2,2-bis ethylphenyl) ethane (4-ethylphenyl) ethane Dicofol Degradation product of dicofol (4,4'-dichlorobenzofeno ne) Disulfoton Disulfoton Disulfoton sulfone Cyhalothrin Cyhalothrin (isomer Cyhalothrin (isomer Diphenylamine Diphenylamine Difenoconazole Difenoconazole (isomer Difenoconazole (isomer Cyfluthrin Cyfluthrin (isomer Cyfluthrin (isomer Cyfluthrin (isomer 3) Cyfluthrin (isomer 4) Diflufenican Diflufenican Cyproconazole Cyproconazole (isomer Cyproconazole (isomer Cypermethrin Cypermethrin (isomer Cypermethrin (isomer Cypermethrin (isomer 3)

9 Cypermethrin (isomer ) Simazine Simazine Spiroxamine Spiroxamine (isomer Spiroxamine (isomer Diazinon Diazinon Di-Allate Di-Allate (isomer Di-Allate (isomer Thiobencarb Thiobencarb Thiometon Thiometon Aldrin/Dieldrin Dieldrin Tecnazene Tecnazene Tetrachlorvinphos (Z)-Tetrachlorvinphos Tebuconazole Tebuconazole Tefluthrin Tefluthrin Deltamethrin/Tralometh rin Deltamethrin (isomer Deltamethrin (isomer Terbutryn Terbutryn Terbufos Terbufos Deltamethrin/Tralometh rin Degradation product of tralomethrin 1 [=Deltamethrin (isomer ] Degradation product of tralomethrin 2 [=Deltamethrin (isomer ] Triadimenol Triadimenol Triadimefon Triadimefon Triazophos Triazophos Tri-allate Tri-allate Triticonazole Triticonazole Tribuphos Tribuphos Triflumizole Triflumizole Trifluralin Trifluralin Trifloxystrobin Trifloxystrobin Nitrapyrin Nitrapyrin Barban Barban Parathion Parathion Parathion-methyl Parathion-methyl Allethrin Bioallethrin (isomer Bioallethrin (isomer Bioresmethrin Bioresmethrin (isomer Bioresmethrin (isomer Picolinafen Picolinafen Bitertanol Bitertanol (isomer Bitertanol (isomer

10 Bifenthrin Bifenthrin Piperonyl butoxide Piperonyl butoxide Pyraclostrobin Degradation product of pyraclostrobin Pyraclofos Pyraclofos Pyrazophos Pyrazophos Pyridaben Pyridaben Pyriproxyfen Pyriproxyfen Pirimicarb Pirimicarb Pirimiphos-methyl Pirimiphos-methyl Pyrimethanil Pyrimethanil Pyrethrins Pyrethrins I Pyrethrins II Vinclozolin Vinclozolin Famphur Famphur Famoxadone Famoxadone Fipronil Fipronil Fenamiphos Fenamiphos Fenarimol Fenarimol Fenitrothion Fenitrothion Fenoxaprop-ethyl Fenoxaprop-ethyl Phenothrin Phenothrin (isomer Phenothrin (isomer Fenobucarb Fenobucarb Fenamidone Fenamidone Fenthion Fenthion Fenvalerate Fenvalerate (isomer Fenvalerate (isomer Fenbuconazole Fenbuconazole Fenpropathrin Fenpropathrin Fenpropimorph Fenpropimorph Buprofezin Buprofezin Furathiocarb Furathiocarb Flamprop-methyl Flamprop-methyl Fluquinconazole Fluquinconazole Fludioxonil Fludioxonil Flucythrinate Flucythrinate (isomer Flucythrinate (isomer Flusilazole Flusilazole Flutolanil Flutolanil Flufenacet Flufenacet Fluridone Fluridone Prochloraz Prochloraz Procymidone Procymidone Propaquizafop Propaquizafop

11 Propanil Propanil Propargite Propargite (isomer 1/isomer Propiconazole Propiconazole (isomer Propiconazole (isomer Propyzamide Propyzamide Profenofos Profenofos Propetamphos Propetamphos Prometryn Prometryn Bromopropylate Bromopropylate Hexachlorobenzene Hexachlorobenzene Benalaxyl Benalaxyl Heptachlor Heptachlor Heptachlor epoxide Permethrin Permethrin (isomer Permethrin (isomer Penconazole Penconazole Pendimethalin Pendimethalin Benfuracarb Benfuracarb Boscalid Boscalid Phosmet Phosmet Phorate Phorate Malathion Malathion Myclobutanil Myclobutanil Methacrifos Methacrifos Methidathion Methidathion Methoxychlor Methoxychlor Methoprene Methoprene Metolachlor Metolachlor S-Metolachlor Mefenpyr-diethyl Mefenpyr-diethyl Resmethrin Resmethrin (isomer Resmethrin (isomer The compounds are listed in the order of the Japanese syllabary, and the isomers are listed by their retention times. Retention indices are obtained based on the retention times of the n-alkanes and show the average values obtained from 2-4 laboratories. Monitoring ions in bold italic font are for quantification; the others are for confirmation. The limit of measurement is the value at S/N=10 when 2 μl of a standard solution is injected into an GC-MS. The limit is the lowest of the values obtained from laboratories. When 2 μl of a test solution prepared by the described method is injected into an GC-MS(/MS), 0.1 ng *1 (0.025 ng *2 for fat sample) corresponds to 0.01 ppm.

12 *1 For test solutions (final volume: 1 ml) prepared using an amount corresponding to 5 g of sample. *2 For test solutions (final volume: 0.5 ml) prepared using an amount corresponding to g of sample (and corresponding to 0.5 g of fat when the sample contains 80% fat).

13 Table 6. Multi-residue Method for Agricultural Chemicals by GC-MS (Animal and Fishery Products:milk, egg and honey) Agricultural chemicals Analytes Reten tion index Monitoring ions (m/z) Limit of measure ment (ng) γ-bhc(lindane) γ-bhc(lindane) DDT o,p'-ddt p,p'-ddd p,p'-dde p,p'-ddt Azamethiphos Azamethiphos Azinphos-methyl Azinphos-methyl Acetamiprid Acetamiprid Acephate Acephate Azoxystrobin Azoxystrobin Atrazine Atrazine Ametryn Ametryn Alachlor Alachlor Aramite Aramite (isomer Aramite (isomer Aramite (isomer 3) Aramite (isomer 4) Aldicarb Degradation product of aldicarb Aldoxycarb Degradation product of aldoxycarb Aldrin/Dieldrin Aldrin Allethrin Allethrin (isomer 1/isomer Allethrin (isomer 3/isomer 4) Isofenphos Isofenphos Isofenphos oxon Isoprothiolane Isoprothiolane Iprodione Iprodione Imazalil Imazalil Fenvalerate Esfenvalerate (isomer Esfenvalerate (isomer Ethion Ethion Etoxazole Etoxazole Ethofumesate Ethofumesate Ethoprophos Ethoprophos Epoxiconazole Epoxiconazole Endosulfan α-endosulfan β-endosulfan Endosulfan sulfate

14 Endrin Endrin Oxadiazon Oxadiazon Oxabetrinil Oxabetrinil Oxyfluorfen Oxyfluorfen Omethoate Omethoate Carbaryl Carbaryl Carfentrazone-ethyl Carfentrazone-ethyl Carboxin Carboxin Carbofuran Carbofuran Quinoxyfen Quinoxyfen Quintozene Quintozene Kresoxim-methyl Kresoxim-methyl Chlorthal-dimethyl Chlorthal-dimethyl Chlordane cis-chlordane trans-chlordane Oxychlordane Chlorpyrifos Chlorpyrifos Chlorpyrifos-methyl Chlorpyrifos-methyl Chlorfenapyr Chlorfenapyr Chlorfenson Chlorfenson Chlorfenvinphos (E)- Chlorfenvinphos (Z)- Chlorfenvinphos Chlorbufam Chlorbufam Chlorbenside Chlorbenside Chloroneb Chloroneb Chlorobenzilate Chlorobenzilate Diclofop-methyl Diclofop-methyl ,1-Dichloro-2,2-bis(4-1,1-Dichloro-2,2-bis ethylphenyl) ethane (4-ethylphenyl) ethane Dicofol Degradation product of dicofol (4,4'-Dichlorobenzofeno ne) Disulfoton Disulfoton Disulfoton sulfone Cyhalothrin Cyhalothrin (isomer Cyhalothrin (isomer Diphenylamine Diphenylamine Difenoconazole Difenoconazole (isomer Difenoconazole (isomer Cyfluthrin Cyfluthrin (isomer Cyfluthrin (isomer Cyfluthrin (isomer 3) Cyfluthrin (isomer 4) Diflufenican Diflufenican

15 Cyproconazole Cyproconazole (isomer Cyproconazole (isomer Cypermethrin Cypermethrin (isomer Cypermethrin (isomer Cypermethrin (isomer ) Cypermethrin (isomer ) Simazine Simazine Dimethoate Dimethoate Dimethomorph Dimethomorph (isomer Dimethomorph (isomer Spiroxamine Spiroxamine (isomer Spiroxamine (isomer Diazinon Diazinon Di-Allate Di-Allate (isomer Di-Allate (isomer Thiacloprid Thiacloprid Thiabendazole Thiabendazole Thiobencarb Thiobencarb Thiometon Thiometon Aldrin/Dieldrin Dieldrin Tecnazene Tecnazene Tetrachlorvinphos (Z)-Tetrachlorvinphos Tebuconazole Tebuconazole Tebuthiuron Degradation product of tebuthiuron Tefluthrin Tefluthrin Deltamethrin/Tralometh rin Deltamethrin (isomer Deltamethrin (isomer Terbutryn Terbutryn Terbufos Terbufos Deltamethrin/Tralometh rin Degradation product of tralomethrin 1 [=Deltamethrin (isomer ] Degradation product of tralomethrin 2 [=Deltamethrin (isomer ] Triadimenol Triadimenol Triadimefon Triadimefon Triazophos Triazophos Tri-allate Tri-allate Triticonazole Triticonazole Tribuphos Tribuphos

16 Triflumizole Triflumizole Trifluralin Trifluralin Trifloxystrobin Trifloxystrobin Norflurazon Norflurazon Barban Barban Parathion Parathion Parathion-methyl Parathion-methyl Allethrin Bioallethrin (isomer Bioallethrin (isomer Bioresmethrin Bioresmethrin (isomer Bioresmethrin (isomer Picolinafen Picolinafen Bitertanol Bitertanol (isomer Bitertanol (isomer Bifenthrin Bifenthrin Piperonyl butoxide Piperonyl butoxide Pyraclostrobin Degradation product of pyraclostrobin Pyrazophos Pyrazophos Pyridaben Pyridaben Pyriproxyfen Pyriproxyfen Pirimicarb Pirimicarb Pirimiphos-methyl Pirimiphos-methyl Pyrimethanil Pyrimethanil Pyrethrins Pyrethrins I Pyrethrins II Vinclozolin Vinclozolin Famphur Famphur Famoxadone Famoxadone Fipronil Fipronil Fenamiphos Fenamiphos Fenarimol Fenarimol Fenitrothion Fenitrothion Fenoxaprop-ethyl Fenoxaprop-ethyl Phenothrin Phenothrin (isomer Phenothrin (isomer Fenobucarb Fenobucarb Fenamidone Fenamidone Fenthion Fenthion Fenvalerate Fenvalerate (isomer Fenvalerate (isomer Fenbuconazole Fenbuconazole Fenpropathrin Fenpropathrin Fenpropimorph Fenpropimorph

17 Buprofezin Buprofezin Furathiocarb Furathiocarb Flamprop-methyl Flamprop-methyl Fluquinconazole Fluquinconazole Fludioxonil Fludioxonil Flucythrinate Flucythrinate (isomer Flucythrinate (isomer Flusilazole Flusilazole Flutolanil Flutolanil Flutriafol Flutriafol Fluvalinate Fluvalinate (isomer Fluvalinate (isomer Flumioxazin Flumioxazin Flumiclorac pentyl Flumiclorac pentyl Fluridone Fluridone Prochloraz Prochloraz Procymidone Procymidone Propaquizafop Propaquizafop Propanil Propanil Propargite Propargite (isomer /isomer Propiconazole Propiconazole (isomer Propiconazole (isomer Propyzamide Propyzamide Profenofos Profenofos Propetamphos Propetamphos Propoxur Propoxur Bromacil Bromacil Prometryn Prometryn Bromopropylate Bromopropylate Hexazinone Hexazinone Benalaxyl Benalaxyl Heptachlor Heptachlor Heptachlor epoxide Permethrin Permethrin (isomer Permethrin (isomer Penconazole Penconazole Bendiocarb Bendiocarb Pendimethalin Pendimethalin Benfuracarb Benfuracarb Boscalid Boscalid Phosmet Phosmet Phorate Phorate Malathion Malathion

18 Myclobutanil Myclobutanil Methamidophos Methamidophos Metalaxyl/Mefenoxam Metalaxyl Methidathion Methidathion Methoxychlor Methoxychlor Methoprene Methoprene Metolachlor Metolachlor S-Metolachlor Metribuzin Metribuzin Mevinphos Mevinphos (isomer Mevinphos (isomer Metalaxyl/Mefenoxam Mefenoxam Mefenpyr-diethyl Mefenpyr-diethyl Resmethrin Resmethrin (isomer Resmethrin (isomer The compounds are listed in the order of the Japanese syllabary, and the isomers are listed by their retention times. Retention indices are obtained based on the retention times of the n-alkanes and show the average values obtained from 2-4 laboratories. Monitoring ions in bold italic font are for quantification; the others are for confirmation. The limit of measurement is the value at S/N=10 when 2 μl of a standard solution is injected into an GC-MS. The limit is the lowest of the values obtained from laboratories. When 2 μl of a test solution prepared by the described method is injected into an GC-MS(/MS), 0.1 ng *1 corresponds to 0.01 ppm. *1 For test solutions (final volume: 1 ml) prepared using an amount corresponding to 5 g of sample.