Computer elimination of voltammogram deformations by catalytic reaction to improve their signal for quantitative analysis. Determination of catalytic rate constant

Abstract

AbstractChemical reactions coupled with the electrode process lead to the change of shape and/or height of the measured voltammogram, thus complicating its application in quantitative analysis. This article describes a fractional differintegration procedure which corrects voltammograms for interference by catalytic reactions while simultaneously providing a value for the catalytic rate constants. A peocedure is proposed which utilizes the change of the shape of a reversible charge transfer voltammogram caused by slow and moderately fast catalytic reaction to the elimination of its influence on the analytical signal. It is based upon computer symmetrization of the voltammogram by fractional differentiation of the optimized order and the following correction of the signal. The procedure also enables an advantageous determination of the catalytic reaction rate constant. Since the height of the symmetrized 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 determination of rate constant were tested with the Ti(III) NH2OH catalytic system.