Liquid chromatographic determination of imazosulfuron in drinking water and in soil using ultraviolet detection

Reversed-phase liquid chromatography (LC) is used to determine a relatively new sulfonylureic herbicide, imazosulfuron, 1-(2-chloroimidazo-[1,2-a] pyridin-3-ylsulfonyl)-3-(4,6-dimethoxy-2-pyrimidinyl)-urea (TH-913), in drinking water and in soil. TH-913 is extracted from water using solid-phase extraction on C18 bonded silica. Soil samples (20 g) are extracted with 300 ml of methanol-water (50:50) and the acidified extracts are transferred onto Sep-Pak C18 and processed as described for water samples. Off-line desorption is done with 20 ml of methanol-water (50:50). The eluate is evaporated to dryness, the residue dissolved in acetonitrile and analysed by LC with UV detection at 238 nm. The recoveries of TH-913 from water were over 95% (at 0.05 microg/l level) and from soil over 90% (at 0.005 mg/kg level).