Monitoring of the herbicide clomazone in environmental water samples by solid-phase extraction and high-performance liquid chromatography with ultraviolet detection

Evaluation of a simple and rapid method for determination of clomazone in environmental water samples, by high-performance liquid chromatography with ultraviolet detection, is described. After solid-phase extraction with C-18 extraction cartridges clomazone was separated on a C-18 column with 65:35 (v/v) methanol-water, pH 4.0, as mobile phase at a flow-rate of 1.0 mL min(-1). After optimization of the extraction and separation conditions, the method was used for determination of clomazone residues in rivers and agricultural waters of the central region of the Rio Grande do Sul province. The results revealed that clomazone persists in agricultural water at least for 130 days, and was present in 90% of the river water samples analyzed.