Multiresidue method for determination of sulfonylurea herbicides in water by liquid chromatography with confirmation by capillary electrophoresis.

A liquid chromatographic method with comfirmation by capillary electrophoresis was used to determine 12 sulfonylurea herbicides in agricultural water. Analysis of 3 different water matrixes fortified at 2 levels gave good recoveries with adequate sensitivity at the 0.1 ppb level. A portion of the water was acidified with acetic acid and loaded onto an RP-102 solid-phase extraction (SPE) cartridge, and the extract was cleaned up on an alumina SPE cartridge. Extracts were desalted with an RP-102 SPE cartridge before instrumentation. Samples needing chemical filtration, such as pond water, required additional cleanup with a SAX SPE cartridge before the alumina cleanup step. Data were compiled for both determinative techniques and evaluated.