RAPID AND SIMULTANEOUS DETERMINATION OF ORGANOPHOSPHORUS PESTICIDES IN AGRICULTURAL PRODUCTS BY FPD-GC

A method for rapid and simultaneous determination of 19 kinds of organophosphorus pesticides was developed by FPD-GC with two kinds of capillary columns (DB-5MS and DB-210). Sample preparation of the 19 pesticides in agricultural products was systematically established as follows. 1) Pesticides in vegetables and fruits were extracted with acetone, reextracted with dichloromethane, and determined by GC. 2) Pesticides in onion were extracted with acetone by homogenation of a frozen sample in dilute phosphoric acid, and re-extracted with dichloromethane. 3) Pesticides in soybean, redbean and hulled rice were extracted with 30% aqueous acetone, then cleaned up with zinc acetate in order to remove some of the components, including fatty acids, as a precipitate, and re-extracted with dichloromethane. 4) Pesticides in green tea were extracted and re-extracted by the same method as in 3). Then the dichloromethane extract was concentrated to dryness, and the residue obtained was extracted with n-hexane in order to remove insoluble components. Recoveries and coefficients of variation of the pesticides in all agricultural products were in the ranges of 46.7 approximately 120% and 0.1 approximately 14.9%, respectively.