Faculté des sciences

Current response of ion-selective solvent polymeric membranes at controlled potential

Sutter, Jolanda ; Morf, Werner E. ; de Rooij, Nicolaas F. ; Pretsch, Ernö

In: Journal of Electroanalytical Chemistry, 2004, vol. 571, no. 1, p. 27-35

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 for corresponding measurements on ion-selective electrode membranes. Here, a theoretical... Plus

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    Summary
    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 for corresponding measurements on ion-selective electrode membranes. Here, a theoretical explanation for the apparent contradiction between the behavior of the two kinds of system is given. Experimental results obtained with conventional ion-selective PVC membranes as well as with membranes based on PVC free membrane matrices are presented.