Determination of chlorsulfuron and tribenuron-methyl residues in agricultural soils

A high-performance liquid chromatography (HPLC) method for the determination of tribenuron-methyl and chlorsulfuron residues on different types of soils is proposed. For the extraction, three procedures using organic solvents, supercritical fluid or solid-phase extraction have been tested. Extraction with water at alkaline pH followed by concentration 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 with acetonitrile-water (containing 0.1% H3PO4) (40:60) as mobile phase and UV detection at 220 nm. The type of soil and its herbicide content affect the recoveries obtained. (C) 1997 Elsevier Science B.V.