Second-harmonic alternating current polarography

Abstract

The technique of second-harmonic a.c. polarography is discussed from the viewpoints of theoretical basis, experimental requirements, and scope of application. The theoretical relation is given for the second-harmonic current-component of a straightforward electrochemical reaction under conditions of a.c, polarography. It is shown how this relation can be used to determine the kinetic parameters (rate constant and transfer coefficient) of the electron-transfer step. Results obtained with the zinc(n)/zinc (mercury) system are in good agreement with those reported in other investigations by other methods. The experimental aspects of second-harmonic studies are examined, and the dependence of the accuracy and reliability of results on various features of the instrumental arrangement is brought out.    Potential applications, particularly in tensammetric studies and in analytical work, are indicated.