Digital Pulse ac Voltammetry for the Simultaneous Analysis of Electroactive and Electrosorptive Species in Flow Systems

A digital two-step and three-step pulse potential ac voltammetry system was proposed and applied for the simultaneous analysis of electrosorptive and electroactive species in flow systems. To perform the ac polarography function, a PC was interfaced to a potentiostat to mimic all the necessary hardware functions of an analog ac polarograph. From the measurement of the change of phase-selective charging current and the zero-order current, I3-, Br- specifically adsorbed and Cd^2+, Pb^2+ reduced at a hanging mercury drop electrode can be determined simultaneously in a FIA and IC system. With the digital pulse ac voltammetrycoupled IC, detection limits as low as 5.0 (mu)M and linear dynamic ranges from 5.0 to 100 or 200 (mu)M with linear correlation coefficients better than 0.9990 were found for the analysis of I3-, Br-, and S2O32-.