Electrically Heated Bismuth-Film Electrode for Voltammetric Stripping Measurements of Trace Metals

Bismuth-coated carbon paste electrodes display an attractive stripping voltammetric behavior which improves greatly upon heating the electrode during the deposition step. Such “hot-electrode” operation leads to a dramatic enhancement of the stripping peaks of lead, cadmium and zinc, while retaining low background currents. The influence of relevant parameters, including the heating current, deposition potential and deposition time is examined. The stripping signals for selected heavy metals result in sharp, well defined and undistorted peaks, with favorable reproducibility (5%). Highly linear calibration plot (correlation coefficient, 0.9986) is observed over the 20–140 μg/L lead range. An estimated detection limit of 3.16 μg/L lead could be observed on the basis of signal-to-noise ratio.