Determination of sulfonylurea herbicides in water by capillary electrophoresis and by liquid chromatography/mass spectrometry.
A capillary electrophoresis (CE) method and an electrospray ionization (ESI) liquid chromatography/mass spectrometry (LC/MS) confirmatory method were developed to analyze 12 sulfonylurea herbicides and one sulfonamide (Flumetsulam) in runoff water. The water used for fortification was collected from a local marsh that contained high levels of potentially interfering compounds. Good recoveries and adequate sensitivity at the 0.2 ppb level (limit of quantitation) were obtained. A portion of the water was acidified and extracted with reversed-phase solid-phase extraction (SPE). Extracts were cleaned up with a tandem system consisting of a strong-anion exchange SPE cartridge stacked on an alumina SPE cartridge. CE/ultraviolet quantitation was achieved by capillary zone electrophoresis at pH 4.75 with 50 mM ammonium acetate buffer and an acetonitrile modifier. ESI LC/MS quantitation was achieved by using a time-scheduled selective-ion monitoring (positive mode) of the M + H ions for each compound. The extraction/cleanup procedure provided extracts such that in-source collision-induced dissociation gave product ions for confirmation at the 0.2 ppb fortification level.
Krynitsky
A J
AJ
U.S. Environmental Protection Agency, Analytical Chemistry Laboratory, Beltsville, MD 20705, USA.
D002853:Chromatography, Liquid; D019075:Electrophoresis, Capillary; D008401:Gas Chromatography-Mass Spectrometry; D006540:Herbicides / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D013056:Spectrophotometry, Ultraviolet; D013453:Sulfonylurea Compounds / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D006540:Herbicides; D007202:Indicators and Reagents; D013453:Sulfonylurea Compounds; D014874:Water Pollutants, Chemical