DETERMINATION OF ALDICARB, ALDICARB SULFOXIDE, AND ALDICARB SULFONE IN ORANGES BY SIMPLE GAS-LIQUID-CHROMATOGRAPHY WITH NITROGEN-PHOSPHORUSDETECTION

A reversed-phase liquid chromatographic method, using an acetonitrile- water gradient mobile phase, and a gas-liquid chromatographic method w ith nitrogen-phosphorus and flame photometric detection were compared for simultaneous and separate determinations of trace quantities of al dicarb and its metabolites aldicarb sulfone and aldicarb sulfoxide. On e hundred gram samples of fortified oranges were extracted with water- acetone, water-acetonitrile, or water-methanol, and the extracts were partitioned with methylene chloride. Partitioning with other organic s olvents such as chloroform, ethyl acetate, or methyl isobutyl ketone w as also investigated. When performed under optimal conditions, the pro cedure has detection limits of 0.4, 0.8, and 0.4 ppb for aldicarb, ald icarb sulfoxide, and aldicarb sulfone, respectively. Recoveries at for tification levels of 4, 20, and 80 ppb ranged from 75 to 90%. Coeffici ents of variation ranged from 8 to 10%.