DEVELOPMENT AND CHARACTERIZATION OF AN AUTOMATED FLOW SYSTEM FOR VOLTAMMETRIC ANALYSIS

A flow system for voltammetric analysis is described and characterized. This system was designed so that sample manipulation and electrochemical experiments could be performed under automated control. The goal of this work is to expand the practical possibilities for elucidation of the electrochemical behavior of chemical systems. An auxiliary goal is to exploit the potential of flow systems combined with pulse voltammetry for chemical analysis. Once a system has been characterized systematically to establish optimal conditions, voltammograms may be subjected to kinetic analysis. The test system employed here is the reduction and anodic stripping of Pb(II). The accuracy of the sample delivery system was tested by producing calibration curves, which were linear over the range of 0-100% mixing, with correlation coefficients greater than 0.999. The introduction of the sample by means of a sample injector was evaluated along with the effect of the carrier flow-rate on anodic stripping voltammograms. The optimum conditions of 1 ml min-1 carrier flow-rate and 150% carrier sweep volume of the loop were determined. Although the flow cell detector is of the wall jet style, the effect of flow-rate on anodic stripping currents is not that of wall jet behavior. The reproducibility of the flow system, for optimum conditions, matched that of the detector for static cell experiments. Finally, the conversion efficiency of the detector was determined to be approximately 1%.