Oxidative amperometric flow injection determination of oxalate at an electrochemically pre-treated glassy carbon electrode

Abstract

An effective electrochemical pre-treatment of a newly polished glassy carbon electrode has been shown to be essential if sensitive and reproducible signals are to be obtained in the oxidative determination of oxalate. Pre-treatment at + 1.75 V for 10 min and then at –1.0 V for 1 min in the 0.05 M phosphate buffer (pH 7.0) used as an eluent for the determination was shown to be effective in producing a well shaped hydrodynamic voltammogram, maximum signal size and improved precision at the measurement potential used (1.5 V). Calibration graphs were rectilinear for up to 100 µg ml^–1 of oxalic acid dihydrate.