1998 Volume 14 Issue 2 Pages 369-373
A simple and sensitive method was developed for the capillary electrophoretic determination of Cr(VI) and Cr(III). In a 0.1 M CClH2COOH-CClH2COONa buffer of pH 2 - 3, Mo(VI) reacts rapidly, even at room temperature with Cr(III), to form a stable heteropolyanion. Both anionic forms of Cr(III) and Cr(VI) can be determined simultaneously by capillary electrophoresis with UV detection at 256 nm. Linear calibration curves were obtained in the concentration ranges of 5×10-6 - 1×10-4 M and 1×10-5 - 1×10-4 M for Cr(III) and Cr(VI), respectively; the detection limits were 2×10-6 and 5×10-6 M (the signal-to-noise ratio=5). Interference from foreign ions is also discussed.