Automated square-wave anodic-stripping voltammetry with a flow-through cell and matrix exchange

An extremely sensitive and versatile instrument is described that performs square-wave anodic-stripping voltammetry. The instrument incorporates a flow-through cell and is capable of changing the solution matrix between the deposition and stripping steps. The working electrode is a static mercury drop electrode constructed in the authors' laboratories. The entire system is controlled by a microcomputer that allows the usual variation of the square-wave parameters, as well as setting of the initial and final scan potentials, the deposition time, the scan-rate, the instrument sensitivity and the drop size. To show the performance of the instrument, calibration graphs for Cd in the ranges 0.2-40 and 0.1-1 ng/ml are described and the reproducibility of the drop is discussed. Analysis of a NaCl sample for Cd is given as an example of application of the method.