Determination of Dichlorvos, Trichlorfon and Their Metabolites and Degradation Products in Environmental Water, Drinks and Human Urine.

Abstract

A systematic analytical procedure for dichlorvos (DDVP) and trichlorfon (DEP), organophosphorus pesticides, and furthermore for desmethyl dichlorvos (DM-DDVP), desmethyl trichlorfon (DM-DEP), dimethyl phosphate (DMP) and monomethyl phosphate (MMP), their metabolites and degradation products, was investigated. From the environmental water, drinks and human urine, after salting-out, only DDVP was first extracted with n-hexane and then the others were extracted with acetonitrile-diethylether (1 : 1, v/v) at about 1N by HCl. TLC was performed on silica-gel plate using acetonitrile-water (85 : 15, v/v) and isopropanol-water-28% ammonium hydroxide (75 : 24 : 1, v/v) as development systems. By colorations with 4-(p-nitrobenzyl) pyridine (NBP) and o-tolidine, they were relatively well detected. It was possible to determine DEP, DM-DDVP, DM-DEP, DMP and MMP by FID-GC and GC-MS after trimethylsilyl derivatization of them with N, O-bis (trimethylsilyl) trifluoroacetamide (BSTFA). The detection limits of their aqueous solution were 0.1-3 μg/ml by FID-GC and 0.2-10 μg/ml by scanning mode GC-MS. The coefficients of variation for their spiked urine sample by GC analysis in this way were 2.7-7.6% at 50μg/ml, respectively.