HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC METHOD FOR THE ANALYSIS OF AMINOCARB, MEXACARBATE AND SOME OF THEIR N-METHYLCARBAMATE METABOLITES BY POSTCOLUMN DERIVATIZATION WITH FLUORESCENCE DETECTION

A sensitive and selective high-performance liquid chromatographic method with post-column derivatization, using o-phthalaldehyde and 2-mercaptoethanol, is described for the analysis of aminocarb, mexacarbate and some of their carbamate metabolites. The separation system consisted of an RP-8 OS (10 mu m) 20 cm x 4.6 mm I.D. column, an acetonitrile-water mobile system and a reactor for the hydrolysis of analytes from column effluents and fluorophore formation. The fluorophores were detected at 230 nm (excitation) and 418 nm (emission). The recoveries of the carbamates in spiked natural water at 2 and 20 ng/ml fortification levels ranged from 72.0 to 98.4% with relative standard deviations of 5.0 to 11.5%. The recoveries for spiked forest soil at 20 and 200 ng/g fortification levels ranged from 74.1 to 97.6% with relative standard deviations of 5.8 to 10.7%. Limits of detection and quantification for all the analytes were 0.1 and 0.4 ng in water and soil, respectively.