Determination of sodium N-methyldithiocarbamate (metham sodium) and methyl isothiocyanate in aqueous samples by high-performance liquid chromatography using a micellar mobile phase

Abstract

A high-performance liquid chromatographic procedure was developed for the simultaneous determination of the fungicides sodium N-methyldithiocarbamate and methyl isothiocyanate. These fungicides were separated on a reversed-phase octadecyl bonded column with micellar hexadecyltrimethylammonium bromide in an eluent of methanol-water (50 + 50 V/V) buffered to pH 6.8 (10 mM phosphate). Detection was carried out at 247 nm with a UV detector. Recoveries of standards added to pond water and untreated sewage were >92% and >88%, respectively, for both fungicides. The detection limits for sodium N-methyldithiocarbamate and methyl isothiocyanate are 70 µg dm^–3(p.p.b.) and 1 µg dm^–3(p.p.b.), respectively.