[Gas chromatographic determination of azinphos-methyl in imported crops]

A gas chromatographic method for the quantitative analysis of azinphos-methyl in agricultural products was studied. Azinphos-methyl was extracted with acetone. The extract was cleaned up by charcoal column chromatography for the treatment of wheat and soybean and by using coagulating reagent for the treatment of lemon and orange, then determined by a gas chromatograph equipped with a flame photometric detector (FPD). The mean recovery of azinphos-methyl added to wheat, soybean and lemon at the level of 0.1 or 0.2 microgram/g was 96.6-101.0%. The detection limit of azinphos-methyl was 0.04 microgram/g in the case of wheat and soybean extracted from 10 g of each sample and 0.02 microgram/g in the case of lemon and orange extracted from 20 g of each sample. Azinphos-methyl was not detected in any of the imported, 6 wheat, 6 soybean, 5 lemon and 4 orange tested using the above mentioned method.