Determination of hexazinone and its metabolites in groundwater by capillary electrophoresis

A micellar electrokinetic chromatographic method was developed to separate and quantify hexazinone and metabolites C, A1, E, B and D in groundwater. Hexazinone and its metabolites were extracted from water using Supelclean ENVI-Carb solid-phase extraction tubes. Quantitation was performed using UV photodiode detection at 220, 225, 230 and 247 nm. Intra-assay and inter-assay reproducibility studies run at 0.5, 1.0, 2.0 and 5.0 ppb indicated the procedure was reproducible. Groundwater samples collected from US Geological Survey monitoring wells were analyzed for hexazinone and its metabolites by CE. A comparison was made between CE and an established HPLC method of the hexazinone and metabolite B. The linear regression for hexazinone was y = 1.007x + 0.219 with a correlation coefficient of 0.96 while the linear regression for metabolite B was y = 1.100x-0.057 with a correlation coefficient of 0.91.