SQUARE-WAVE ANODIC-STRIPPING VOLTAMMETRY IN STATIONARY AND FLOWING SOLUTION - A COMPARATIVE-STUDY

A comparison has been made between square-wave anodic stripping voltammetry (SWASV) at a stationary, mercury thin-film electrode and at a wall-jet mercury thin-film electrode in flowing solution using cadmium(II) and lead(II) as test species. Mercury thin films were prepared on glassy carbon electrode substrates. The effects of square wave amplitude and frequency on the peak current and peak potential in the determination step were studied, and these parameters optimized. Deposition time was varied, and the effect of flow rate in flowing solution investigated. Practical detection limits were found to be 10(-8) mol l(-1) at stationary electrodes and 2 x 10(-9) mol l(-1) at wall-jet electrodes. It was found that SWASV gives good results in the presence and absence of dissolved oxygen for both analysis modes, which augurs well for its future application in dow systems, and particularly at wall-jet electrodes.