GC-FPDによる食品中の残留農薬の分析 : 小麦粉中の残留有機リン系農薬の分析

The residual organophosphorus pesticides of chlorphyrifos-methyl and malathion in wheat flours were analyzed by gas chromatography with flame-photometric detector (GC-FPD). Organophosphorus pesticides were extracted with acetone from 20g of the samples and the extract was treated with an aquenous phosphoric acid-ammonium chloride solution. The solution was filtered in the presence of Celite 545 and the filtrate was concentrated to give an aqueous solution. The solution was extracted with ethyl acetate and then washed with 2% sodium chloride solution. After drying over anhydrous sodium sulfate, the extract was evaporated to dryness and reconstituted in 5ml of acetone. The resulting solution was used as an analytical sample without further cleanup. Chlorpyrifos-methyl was detected from 12 among 21 flour samples with concentration range of 0.01-0.37μg/g and malathion was found in 7 among 21 samples with a concentration range of 0.01-0.15μg/g. The detection limit was 0.005μg/g for wheat flours