Studies with the aid of high-performance liquid chromatography on the behaviour of metribuzin during water treatment

An extraction procedure, followed by high-performance liquid chromatographic separation, is described for the determination of metribuzin, a triazin derivative employed as a herbicide, in water. For concentrations of 2.5 to 10 ug per litre recoveries ranged from 77 to 85 per cent, with standard deviations of 4.5 to 13.3 per cent. The method was applied to monitor the fate of the herbicide during some water-treatment processes; no significant decrease in the level of metribuzin was recorded during slow sand filtration or chlorination, but adsorption on activated carbon resulted in almost quantitative removal. Traces of certain metabolites formed during sand filtration and chlorination were detected and identified with the aid of UV spectroscopy and mass spectrometry.