STUDIES ON SIMPLE CLEANUP BY THE PRECIPIT ATION METHOD AND GC MS ANALYSIS AFTER BENZYL DERIVATIZATION FOR CARBAMATE PESTICIDES IN AGRICULTURAL PRODUCTS/

A simple and rapid sample preparation method was developed for the det ermination of carbamate pesticides in agricultural products. The metho d consisted of methanol extraction, purification by addition of zinc s ulfate and sodium tetraborate and reextraction with dichloromethane. H eat-labile carbamate pesticides were hydrolyzed with NaOH and determin ed by gas chromatography-mass spectrometry after benzyl derivatization . The recoveries of 12 kinds of carbamate pesticides fortified at 0.04 similar to 0.4 ppm in 15 kinds of samples ranged from 63.8 to 134.8% with detection limits of 0.005 similar to 0.02 ppm, depending on the c ompounds. The procedure was applied to 309 products. Methomyl or thiod icarb was detected at 0.02 similar to 0.15 ppm in four domestic vegeta bles (cucumber, eggplant, etc.). Carbaryl was detected at 0.01 similar to 0.09 ppm in seven fruits (orange, apple, etc.).