Enhanced resolution of copper and bismuth by addition of gallium in anodic stripping voltammetry with the bismuth film electrode

This paper presents the enhanced analysis of copper on a bismuth electrode upon addition of gallium(III). The presence of gallium alleviates the problems of overlapping stripping signals usually observed between copper and bismuth when using the Bismuth Film Electrode. In addition, it has been found that the presence of gallium improves the reproducibility of the bismuth stripping signal. Simultaneous deposition of copper and bismuth at - 1500 mV for 2 minutes in a supporting electrolyte composed of 0.1 M pH 4.75 acetate buffer with 250 mu g L-1 gallium yields well resolved copper and bismuth signals when analyzed with square-wave anodic stripping voltammetry. Simultaneous analysis of copper and lead yielded linear calibration plots in the range 10 to 100 mu g L-1 with regression coefficients of 0.997 and 0.994 respectively. The theoretical detection limit for copper was calculated to be 4.98 mu g L-1 utilizing a 2 minutes deposition time. ne relative standard deviation for a copper concentration of 50 mu g L-1 was 1.6% (n = 10).