DIRECT DETERMINATION OF BROMACIL AND DIURON RESIDUES IN ENVIRONMENTALWATER SAMPLES BY COUPLED-COLUMN LIQUID-CHROMATOGRAPHY AND LARGE-VOLUME INJECTION

A rapid procedure For the determination of two herbicides in environme ntal water samples is described. The method makes use of the potential of coupled-column liquid chromatography for the trace determination o f 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, rende ring an overall procedure with a throughput of 50 samples per day. Dri nking 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 sta ndard deviations between 3-8%. The calibration graphs are linear over at least three orders of magnitude.