DETERMINATION OF CHLORSULFURON AND TRIBENURON-METHYL RESIDUES IN AGRICULTURAL SOILS

A high-performance liquid chromatography (HPLC) method for the determi nation of tribenuron-methyl and chlorsulfuron residues on different ty pes of soils is proposed. For the extraction, three procedures using o rganic solvents, supercritical fluid or solid-phase extraction have be en tested. Extraction with water at alkaline pH followed by concentrat ion on octadecylsilane is the most advisable for chlorsulfuron, while for tribenuron-methyl, the use of methanol-modified supercritical CO2 is more adequate. The extracts are analyzed by reversed-phase HPLC wit h acetonitrile-water (containing 0.1% H3PO4) (40:60) as mobile phase a nd UV detection at 220 nm. The type of soil and its herbicide content affect the recoveries obtained. (C) 1997 Elsevier Science B.V.