Potential Step Voltammetry of Ion-Transfer at Liquid/Liquid Interface with Preceding Chemical Reaction. Determination of the Rate and Equilibrium Constants from Voltammetric Curves

Abstract

Abstract Theoretical equations of the potential step voltammograms for the ion-transfer with preceding chemical reaction have been derived. Results were applied to analyze the voltammetric behavior of 1,4,7,10,13,16-hexathiacyclooctadecane-assisted transfer of Pb2+ ion across the nitrobenzene/water interface from aqueous medium containing citrate3− ion. The dissociation and association rate constants and the equilibrium constant of Pb2+–citrate3− complex in aqueous medium are determined to be 1.2 × 104 s−1 and 1.2 × 1010 M−1 s−1 and 106.0 M−1, respectively. The results are compared with those obtained by potential sweep voltammetry.