Determination of DDTs and Dicofol Residues in Vegetables by GC/MS and HPLC

Transcription

1 Ann. Rep. Tokyo Metr. Res. Lab. P.H., 51, , 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, DDT GC/MS 5 7 o,p'-ddt p,p'-ddt DDT GC/MS dicofol GC 4,4'-dichlorobenzophenone 4,4'-DCB dicofol Tama Branch Laboratory, The Tokyo Metropolitan Research Laboratory of Public Health, 16 25, Shibazakicho, Tachikawa, Tokyo, Japan

2 136 Ann. Rep. Tokyo Metr. Res. Lab. P.H., 51, 2000 Envi-Carb/LC-NH2 500mg 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 ppm 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 eV 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 nm nm20 l g100ml 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

3 51, n ml 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 ppm 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, ppm 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 ppm DDT o,p'-ddt p,p'- DDT g 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 beans p,p'-ddt Dicofol Young o,p'-ddt soybeans p,p'-ddt Dicofol DDTs spiked at g/g and dicofol at 0.40 g/g Table 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 beans p,p'-ddt Dicofol Young o,p'-ddt soybeans p,p'-ddt Dicofol Detection limits DDTs g/g, dicofol g/g 11.3o,p'-DDT 102% 81% p,p'-ddt 116% 80% % 100% GC/MS ppb DDT Table 2 o,p'-ddt /g /g /g p,p'-ddt GC GC/MS-SIM GC/MS

4 138 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 nm Fig. 3 dicofol230nm Fig. 4Zorbax C8 20, dicofol 0.1 ppm DDT dicifol 0.40 g/g dicofol Table % dicofol DDT Table 2 dicofol g/g UV dicofol p,p'- DDT 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 g/g

5 51, dicofol g/g SPEED Rothman, A. M. J. Assoc. Off. Anal. Chem., 63, , Rathor, H. R. and Wood, R. J. Pestic. Sci., 12, , Yosida,M., Fujita,T., Kurihara,N., et al. Pestic. Biochem. Physiol., 23, 1-6, Gold,B., Leuschen,T., Brunk,G., et al. Chem. Biol. Interact., 35, , 1981