Performance of a general-purpose electrochemical instrument aided by a stand-alone microcomputer system in trace analysis

The features of a microprocessor-based data acquisition and control unit, dedicated to electrochemical experiments, are described. The menu-selectable software allows smoothing, baseline drawing and subtraction as well as differentiation, even with signal amplitudes of some tenths of nA at signal/noise ratios lower than one, without forcing the data to follow theoretical models. Concentrations of cadmium ion as low as 2 × 10^?7, 5 × 10^?8 and 5 × 10^?9 M can be measured, within 10% accuracy and precision, by using sampled d.c. polarography, staircase voltammetry and fast-sweep differential pulse voltammetry, respectively; this is a consistent improvement on literature data. Depending on the electrochemical technique used, the most significant signal parameters, including derivatives, are measured automatically, listed and used in the decision-making process for chemical characterization.