COMPUTER ELIMINATION OF VOLTAMMOGRAM DEFORMATIONS BY CATALYTIC REACTION TO IMPROVE THEIR SIGNAL FOR QUANTITATIVE-ANALYSIS - DETERMINATION OF CATALYTIC RATE-CONSTANT

Chemical reactions coupled with the electrode process lead to the chan ge of shape and/or height of the measured voltammogram, thus complicat ing its application in quantitative analysis. This article describes a fractional differintegration procedure which corrects voltammograms f br interference by catalytic reactions while simultaneously providing a value for the catalytic rate constants. A procedure is proposed whic h utilizes the change of the shape of a reversible charge transfer vol tammogram caused by slow and moderately fast catalytic reaction to the elimination of its influence on the analytical signal. It is based up on the computer symmetrization of the voltammogram by fractional diffe rentiation of the optimized order and the following correction of the signal. The procedure also enables an advantageous determination of th e catalytic reaction rate constant. Since the height of the symmetrize d signal is more sensitive to the catalytic process than the height of the original voltammogram, it is of special importance for lower rate constant values. Both elimination of catalytic influence and the dete rmination of rate constant were tested with the Ti(III) NH2OH catalyti c system.