Systematic errors in the calculation of kinetic parameters by the polarographic method

Abstract

In this paper we have determined the systematic errors introduced in the calculation of some kinetic parameters, such as Tafel slopes and reaction orders, on applying both the Butler—Volmer equation and the rate-determining step approximation at potentials corresponding to the foot of the polarographic waves. These determinations have been carried out using the general i — E relations for the waves, which are obtained from implicit functions found in the literature. Our results indicate that in the mechanism involving dimerization reactions, the errors must be taken into account (including the zone where i < 0.05 i L), since these are greater than those corresponding to the other mechanisms. In order to check these results, two processes have been studied: the reduction of monoethylfumarate and the reduction of benzophenone. Close agreement was found with the experimental results in all cases.