Current Response of Ionophore-Based Ion-Selective Electrode Membranes at Controlled Potential

Abstract

From electrochemical measurements at the interface of two immiscible electrolytes, the current at controlled potential is usually a linear function of the ion concentration in the aqueous phase. Surprisingly, a linear relationship between the current and the logarithm of the sample ion activity is found here for corresponding measurements on ion-selective electrode membranes. Here we document these new findings and give a theoretical explanation for the apparent contradiction between the results obtained with the two kinds of systems.