Determination of chloro- and methylthiotriazine compounds in human urine: extraction with diethyl ether and C18 solid-phase extraction for gas chromatographic analysis with nitrogen-selective and electron capture detection

Abstract

This paper describes an evaluation of extraction methods of triazine herbicides atrazine, simazine, prometryn, and ametryn and of three chlorodealkylated atrazine metabolites from human urine using diethyl ether and C18 solid-phase extraction (Sep-Pak C18 cartridges). The extracts were analysed by capillary gas chromatography using nitrogen selective and electron capture detectors. At ngml−1 concentrations the diethyl ether extraction recoveries of atrazine and simazine were almost quantitative (R.S.D. 10%), while the recoveries of other triazines ranged from 58% for deisopropylatrazine to 85% for deethylatrazine (R.S.D. 19–34%). The sensitivity of the method using a nitrogen selective detector ranged from 5ngml−1 for atrazine to 30ngml−1 for didealkylated atrazine. C18 solid-phase extraction with acetone as eluting solvent resulted in about 100% recoveries of all parent herbicides (R.S.D. 15–21%) with detection limits of 5ngml−1 for atrazine and 10ngml−1 for other herbicides. Comparably high recoveries of three dealkylated atrazine metabolites (R.S.D. 10–12%) were achieved from acidified urine samples (pH 2–3) only at concentrations lower than 100ngml−1. The diethyl ether extraction procedure served to identify occupational exposure to atrazine and simazine. Deethyldeisopropylatrazine was confirmed as the predominant urinary dealkylated metabolite followed by monodealkylated metabolites and unchanged atrazine.