The dependence of the dropping mercury electrode potential at constant current on the concentration of an electroactive constituent involved in reversible or irreversible electrode reactions

Abstract

A new method is described in which the potential of the d.m.e. is measured as a function of the concentration of an electroactive constituent when a constant current is maintained by adjusting the voltage applied to the polarographic cell. Equations are derived describing the expected potential change caused by changing the concentration of a constituent involved in a reversible or an irreversible electrode reaction. Graphical interpretations of the derived equation are made, indicating the most suitable conditions for performing potential measurements, yielding potential differences that greatly exceed those obtained by conventional potentiometry, especially when the method is applied to irreversible electrode reactions at the d.m.e. Experimental evidence is presented, which not only verifies all expectations, but also indicates that the method offers a new approach to the investigation of some fundamental problems.