Separation of phenylurea pesticides by ion-interaction reversed-phase high-performance liquid chromatography - Diuron determination in lagoon water

An ion-interaction HPLC method is developed for the separation of the phenylurea herbicides asulam, diuron, isoproturon, linuron and monuron. C-18 was used as stationary phase and octylammonium phosphate as ion-interaction reagent, in the presence of methanol or acetonitrile as organic modifier. Detection limits lower than 9 mu g/l can be obtained without preconcentration steps. The method was applied to the analysis of diuron in a sample of lagoon water. Using liquid-liquid extraction, a diuron concentration of 42 mu g/l was found.