Ion transport across bilayer lipid membranes in the presence of tetraphenylborate.

A pair of symmetrical cathodic and anodic peaks is observed in cyclic voltammograms for the ion transport across a bilayer lipid membrane (BLM) between two aqueous phases in the presence of tetraphenylborate (TPhB-). Although TPhB- serves as a carrier of a hydrophilic counter ion (Na+) under the steady-state condition, the reason for the appearance of symmetrical peaks has not been clearly explained until now. From the chronoamperometric analysis, it is turned out that the symmetrical peaks are attributed to the translocation of TPhB- between two adsorbed layers on the surface of the BLM.