Direct determination of bromacil and diuron residues in environmental water samples by coupled-column liquid chromatography and large-volume injection

A rapid procedure For the determination of two herbicides in environmental water samples is described. The method makes use of the potential of coupled-column liquid chromatography for the trace determination of polar compounds by direct large-volume injection of aqueous samples. With direct injection of 2000-mu 1 samples, detection limits dawn to 0.1 mu g/l and an analysis time of about 10 min can be achieved, rendering an overall procedure with a throughput of 50 samples per day. Drinking and surface water samples spiked at levels between 0.2 and 1 mu g/l yielded average recoveries between 83-107% (n=5) with relative standard deviations between 3-8%. The calibration graphs are linear over at least three orders of magnitude.