A.c. voltammetric evidence for the transient adsorption of asymmetric ionsin the transfer across the nitrobenzene-water interface

A.c. impedance studies of the ion transfer have evidenced the transient ads orption of xanthene-type anions and other ions having asymmetric charge dis tribution at the nitrobenzene-water interface. The phase angle of the charg e transfer admittance becomes smaller than unity at the potentials beyond t he midpoint potential of the ion transfer. This anomaly does not appreciabl y depend on the sign of the ionic charge or the location of the midpoint po tential, as predicted by the theory proposed recently based on the thermody namic reasoning of the adsorption and ion partitioning of surface active io ns in electrochemical liquid-liquid two-phase systems [T. Kakiuchi, J. Elec troanal. Chem. 496 (2001) 137]. (C) 2001 Elsevier Science B.V. All rights r eserved.