2004 Volume 27 Issue 11 Pages 715-720
A simple and rapid method was developed for the determination of zinc, cadmium, copper and lead at the mg·kg-1 level in soil samples by anodic stripping voltammetry using a mercury film microelectrode (surface area, 240μm2). Pre-electrolysis was performed at -1.3V vs. Ag/AgCl for 2min with stirring in a 0.1mol·l-1 acetic acid-sodium acetate buffer solution (pH 4.2). After the stirring was stopped, anodic stripping voltammograms for deposits were recorded in the potential range of -1.3 to 0.15V vs. Ag/AgCl at a scan rate of 50mV·s-1 in a differential pulse mode. Calibration curves (peak height vs. concentration) were linear (correlation coefficient >0.999) over the 0.2 to 10μg·l-1 concentration range with a relative standard deviation of approximately 5% for 1μg·l-1 (n=5). The detection limits (3σ) calculated from the repeated determination of 0.1μg·l-1 metal ions for a deposition time of 2min ranged from 0.04 to 0.07μg·l-1. Possible interferences were evaluated. This method was successfully applied to the simultaneous determination of zinc, cadmium, copper and lead in several soil samples without any separation steps of matrix elements. The time required for an analysis was within 3min.
