Liquid chromatography with electrocatalytic detection of oxalic acid by a palladium-based glassy carbon electrode

Cyclic voltammetry, how injection analysis and liquid chromatography experi ments were performed to characterise a palladium-modified glassy carbon ele ctrode as an amperometric sensor for the determination of oxalic acid in pe rchloric acid solutions. The effects of several common interferents on the amperometric signal were also evaluated. The electrode stability, precision , limit of detection and linear range were evaluated at a constant applied potential of 1.1 V vs. Ag/AgCl. Calibration plots, obtained using liquid ch romatography, were linear from 0.2 mu M to 1.2 mM (r(2) = 0.9986) and the d etection limit was 0.15 mu M for a 50-mu l injection. An example of analyti cal application, which includes the chromatographic separation and detectio n of oxalic acid in human urine, is given. (C) 1999 Elsevier Science B.V. A ll rights reserved.