Determination of amitrole and urazole in water samples by capillary zone electrophoresis using simultaneous UV and amperometrical detection

In this paper, capillary zone electrophoresis with amperometric detection (CZE-AD) was first applied to the simultaneous separation and determination of amitrole and urazole in water samples. A simple end-column electrochemical detector was used in combination with a commercially available capillary electrophoresis instrument with UV detection. The effects of several important factors were investigated to find optimum conditions. A carbon disk electrode was used as working electrode. Separation and determination of these compounds in water samples were performed in 0.030 mol l(-1) acetate buffers at pH 4.5, 25 kV as separation voltage and the samples were introduced by hydrodynamic mode for 1.5 s. Most of the studies realized showed that the direct electrochemical detection is more sensitive and selective than UV detection. Under the optimum conditions, excellent linearity was observed between peak amperometric signal and analyte concentrations in the range of 0.19-1.35 mg l(-1) for amitrole and 0.20-1.62 mg l(-1) for urazole. The detection limits were 63 and 68 mu g I` for amitrole and urazole, respectively. The utility of this method was demonstrated by monitoring water samples, and the assay results were satisfactory. The detection limits using a previous preconcentration step for amitrole and urazole in spiked mineral water samples were 0.6 and 1.0 mu g l(-1) for amitrole and urazole, respectively. (c) 2005 Elsevier B.V. All rights reserved.