Ann. Rep. Tokyo Metr. Res. Lab. P.H., 51, 135-139, 2000 GC/MS HPLC DDT dicofol Determination of DDTs and Dicofol Residues in Vegetables by GC/MS and HPLC HIROSHI SATOH, NORIO OHASHI, CHIEKO TAKADA, EIKO AMAKAWA, MICHIKO MIYAKODA, TSUTOMU OGIWARA, YOKO AOYAGI and SUKEJI SUZUKI The analytical method to determine o,p'-ddt, p,p'-ddt(ddts)by GC/MS and dicofol by HPLC in vegetables was studied. DDTs and dicofol were extracted with acetone and internal standard (DDT-d8)was added to acetone extract. The acetone extract was evaporated under reduced pressure. Residual aqueous solution was mixed with 6% NaCl solution, then shaked with n-hexane. The organic layer was evaporated and the residue was cleaned up with Envi-carb/LC-NH2 cartridge. In young soybeans, Extrelut 3 was used for removal of lipids. Stable isotope of DDTs was used as an internal standard by GC/MS-SIM. This proposed method showed good recoveries. Using HPLC, dicofol was separated from DDTs and their metabolites using a Zorbax C 8 column with methanol-water-acetic acid(80:20:0.2)as the mobile phase, then detected at 230nm. Dicofol, which was difficult to determine accurately because of pyrolysis in GC/MS analysis, could be determined quantitatively and showed good recoveries by HPLC. In frozen young soybeans and kidney beans, DDTs and dicofol, which may be endocrine disrupting chemicals, were detected. Keywords pesticide residues vegetables endocrine disrupting chemicals DDT dicofol stable isotope standard / GC/MS HPLC photodiode array detector DDT DDD DDE dicofol Fig.1 1 endosulfan, heptachlor epoxide, DDT 2, 4 2 4 DDT GC/MS 5 7 o,p'-ddt p,p'-ddt DDT GC/MS dicofol GC 4,4'-dichlorobenzophenone 4,4'-DCB dicofol 190-0023 16 25 Tama Branch Laboratory, The Tokyo Metropolitan Research Laboratory of Public Health, 16 25, Shibazakicho, Tachikawa, Tokyo, 190-0023 Japan
136 Ann. Rep. Tokyo Metr. Res. Lab. P.H., 51, 2000 Envi-Carb/LC-NH2 500mg 10 3. 1 GC/MS / Finniganmat Fig. 1. Chemical Structures of DDTs and Their Related Compounds PDAHPLC 8 11 dicofol DDT o,p'-ddt p,p'-ddt dicofol 10 o,p'-ddt p,p'-ddt o,p'-ddd p,p'-ddd o,p'-dde p,p'-dde dicofol1 4,4'-DCB 1 10ppm 50.0mg GC/MS n- HPLC50ml 1000ppm n- 100 ppm 10 ppm n- ppm dicofol o,p'-ddt-d8 p,p'-ddt-d8 1 10ppm o,p'- DDT-d8 p,p'-ddt-d8 50.0mg n- 50ml n-100 0.2ppm 10ppm n- Extrelut 3 TRACKERHP-5MS 0.25mm i.d. 30m 0.10 m He 12psi 40 (2min) 10 /min 280 min) 10 /min 290 2min 80 260 250 70eV EI SIM2 l 3. 2 HPLC LC10AT PDA SPD-M10A SIL- 10A CLASS-LC10 1 Zorbax C8 4.6mm i.d. 250mm 5 m Lichrospher RP-18 5 m 1.2ml/min 40 80 20 0.2 230nm 220 300nm20 l 4. 1 50g100ml 10,000rpm 50ml 250ml 20g100ml 0.2ppm ml 4030ml % 50ml n- 50ml n- n- n-, n- ml 4. 2 ml Extrelut 3 Extrelut 3 20ml n- ml 4. 3 ml
51, 2000 137 n- 95 20ml ml ENVI-Carb/LC-NH2 20ml, ml GC/MS HPLC 5 GC/MS o,p'-ddt p,p'-ddt 5. 1 o,p'-ddt p,p'-ddt 0.005 0.1ppm n- o,p'-ddt-d8 p,p'-ddt-d8 0.1ppm 3 1, DDT m/z 235 DDT-d8 m/z 243 DDT DDT-d8 5. 2, g/g 0.1ppm ml 10g HPLC dicofol 3 2, 0.1 1.0ppm dicofol GC/MS- SIM o,p'-ddt p,p'-ddt o,p'-ddt p,p'-ddt d8 GC/MSo,p'-DDT p,p'-ddt o,p'-ddt-d8 p,p'-ddt-d8 d8 o,p'-ddt p,p'-ddt 0.005 0.1ppm DDT o,p'-ddt p,p'- DDT g 0.008 g Table 1 o,p'-ddt105% 95% 3.5, 13.9 p,p'-ddt 192% 77% 12.3, Table 1. Recoveries of DDTs and Dicofol from Vegetables n=3 DDTs GC/MS-SIM HPLC Sample and Internal standard method Direct calibration method dicofol Recovery S.D. Recovery S.D. Recovery S.D. (%) (%) (%) Kidney o,p'-ddt 102 1.8 105 3.5 beans p,p'-ddt 116 6.6 192 12.3 Dicofol Young o,p'-ddt 81 1.3 95 13.9 soybeans p,p'-ddt 80 3.8 77 11.3 Dicofol DDTs spiked at 0.008 g/g and dicofol at 0.40 g/g Table 2. 89.4 1.2 75.6 2.3 Concentration of DDTs and Dicofol in Vegetables DDTs GC/MS-SIM HPLC Sample and Internal standard method Direct calibration method dicofol ( g/g) ( g/g) ( g/g) Kidney o,p'-ddt 0.011 0.013 beans p,p'-ddt 0.001 0.002 Dicofol 0.065 Young o,p'-ddt 0.013 0.026 soybeans p,p'-ddt 0.004 0.009 Dicofol 0.348 Detection limits DDTs 0.001 g/g, dicofol 0.010 g/g 11.3o,p'-DDT 102% 81% 1.8 1.3 p,p'-ddt 116% 80% 6.6 3.8 192% 100% GC/MS ppb DDT Table 2 o,p'-ddt 0.011 0.013 /g 0.013 /g 0.026 /g p,p'-ddt GC GC/MS-SIM GC/MS
138 Ann. Rep. Tokyo Metr. Res. Lab. P.H., 51, 2000 Fig. 2. GC/MS-SIM Chromatograms of DDTs and Their Related Compounds Fig. 3. UV Spectra of DDTs and Their Related Compounds PDA HPLC dicofol GC/MS dicofol 4.4'-DCB dicofol dicofol HPLC-PDA Fig.2 o,p'-ddt p,p'-ddd DDT dicofol UV 220 270nm Fig. 3 dicofol230nm Fig. 4Zorbax C8 20, dicofol 0.1 ppm DDT dicifol 0.40 g/g dicofol Table 1 75.6 89.4% dicofol DDT Table 2 dicofol 0.065 0.348 g/g UV dicofol p,p'- DDT 12 14 dicofol DDT HPLC GC/MS, dicofol Fig. 4. HPLC Chromatograms of Standard Mixture of DDTs and Their Related Compounds and Kiduey Beans Extract Spiked Dicofol 1 : 4,4'-DCB, 2 : p,p'-ddd, 3 : o,p'-ddd, 4 : dicofol, 5 : o,p'- DDE, 6 : p,p'-ddt, 7 : o,p'-ddt, 8 : p,p'-dde GC/MS-SIM DDT HPLC-PDA DDT dicofol GC/MS 4,4'-DCB dicofol HPLC DDT 0.012 0.017 g/g
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