COMPARISON OF LIQUID-CHROMATOGRAPHY ATMOSPHERIC-PRESSURE CHEMICAL-IONIZATION MASS-SPECTROMETRY AND LIQUID-CHROMATOGRAPHY POSTCOLUMN FLUOROMETRY FOR DETERMINATION OF CARBAMATES IN FOOD

Two detection methods, postcolumn derivatization with fluorescent dete ction and atmospheric pressure chemical ionization/mass spectrometry ( MS) were compared for determination of N-methyl carbamates in food by liquid chromatography. Five commodities were spiked with 11 carbamates at levels from 10 to 100 ppb, extracted, and cleaned up by using a me thod based on the AOAC official method. With each detection method, sa mple blanks showed false-positive responses, indicating that neither m ethod alone provides definitive identification, Except for aldicarb su lfoxide determined by MS, recoveries were linear between 10 and 100 pp b. Agreement between the 2 methods was good for determination of recov eries at 25 ppb. Coefficients of variation were 11-33% for fluorescenc e detection and 9-26% for MS.