Simplified method for the determination of residues of carbofuran and its metabolites in crops using gas-liquid chromatography-mass fragmentography.

The gas-liquid chromatographic behaviour of 2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate (carbofuran), its 3-keto-, and 3-hydroxy-derivatives, their respective phenolic hydrolysis products and the heptafluorobutyryl (HFB) derivatives of the carbamates and phenols were studied by examining the column effluent using chemical ionization mass spectrometry. In contrast to the behaviour of the carbamates, their HFB derivatives consistently produced ions having intensities proportional to the quantities injected. The common base-peak ion at 228 a.m.u. was used to quantitate these materials at the 0.02-1 ppm level in field-treated carrots, celery, tomatoes and corn with minimal sample preparation.