Analysis of N-methylcarbamates insecticides and some of their main metabolites in urine with liquid chromatography using diode array detection and electrospray mass spectrometry

Commonly used N-methylcarbamates, i.e., aldicarb and carbofuran and some of their main metabolites as aldicarb sulphoxide and aldicarb sulphone for al dicarb and 3-hydroxycarbofuran for carbofuran were extracted from human uri ne by off-line solid phase extraction with graphite carbon and subsequently clean up with NH2-modified silica. Analyte fractionation and quantificatio n were performed by liquid chromatography (LC) with UV detection. The recov ery efficiencies of the tested compounds yielded more than 81% at the forti fication level of 0.05 mu g/ml in urine and their relative standard deviati ons were between 6 and 16%. The detection limits of each compound ranged be tween 4 and 10 mu g/l. This method involves confirmatory analysis by LC-ele ctrospray mass spectrometry (MS) instrumentation equipped with a single qua drupole mass filter MS data acquisition was performed by time-scheduled sel ected ion monitoring (SIM) program. Limits of detection giving values betwe en 0.1 and 0.5 mu g/l. Urine samples from a pest control operator were anal yzed and the analytes were not found. (C) 2000 Elsevier Science B.V. All ri ghts reserved.