Small-type electrolytic cell for ion-transfer polarography with ascending water electrode

Abstract

A small-type electrolytic cell for polarographic studies of ion-transfer at the oil/water interface with an ascending water electrode was constructed and its performance was examined. A small orifice for channeling ascending water drops into the oil phase was drilled in the center of a Teflon disk (10mm diameter, 5mm thickness), which was then incorporated into a three-electrode type electrolytic cell requiring only 0.5 cm³of the oil phase. This electrolytic cell was tentatively applied to study some ion transfer processes at the nitobenzene/water interface, viz. (1) the transfer of tetramethylammonium ion, and (2) the facilitated transfer of K⁺ by valinomycin. The current-potential curves due to the ion transfer processes were as well-defined as those obtained with a conventional, large-type electrolytic cell. For the transfer process (2), the current maximum appeared around the limiting current, but it was suppressed effectively by the addition of Span^®20 (sorbitan monolaurate) in the nitrobenzene phase.