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Equilibrium potential of potentiometric ion sensors under steady-state current by using current-reversal chronopotentiometry

2001; Elsevier BV; Volume: 509; Issue: 1 Linguagem: Inglês

10.1016/s0022-0728(00)00515-5

1873-2569

Johan Bobacka, Andrzej Lewenstam, Ari Ivaska,

Electrochemical sensors and biosensors

Potentiometric ion sensors based on a solvent polymeric ion-sensing membrane and a conducting polymer as the solid contact were investigated by current-reversal chronopotentiometry. The low-frequency electrochemical behavior of the electrodes resembles a series RC equivalent circuit. The resistance R was attributed primarily to the bulk resistance of the ion-sensing membrane and the capacitance C was attributed to the bulk redox capacitance of the conducting polymer layer acting as an ion-to-electron transducer. It is shown that the equilibrium potential of the ion sensors can be obtained in the presence of a steady-state current by using current-reversal chronopotentiometry (double current step chronopotentiometry).