Simultaneous determination of N-methylcarbamate pesticides and their metabolites in agricultural products

We investigated the determination of N-methylcarbamate pesticides and their metabolites in agricultural products by HPLC with post-column fluorescence detection after clean-up with an SPE cartridge. The homogenate of agricultural products was extracted with acetone. The crude extract was partitioned between 5% sodium chloride solution and dichloromethane, and the dichloromethane layer was concentrated to dryness. The residue was dissolved with a mixture of acetone and n-hexane, and purified by using Supelclean(TM) ENVI(TM)-Carb SPE, Bond Elut((R)) Extraction Cartridge PSA and SAX in series with a mixture of acetone and n-hexane. N-Methylcarbamate pesticide was analyzed by HPLC with post-column reaction and fluorescence detection. N-Methylcarbamate pesticide in citrus fruits and various kinds of agricultural products could be analyzed accurately by the presented method. Recoveries of N-methylcarbamate pesticides added to several agricultural products at the level of 0.10 ppm were mostly in the range of 60similar to110%. The limit of detection was 0.005 ppm.