Standard potentials for the transfer of ions at the oil/water interface

Abstract

The standard potential of ion transfer at the oil/water interface (Δ_o^wΦ_i°), which is related to the standard Gibbs energy of ion transfer (ΔG°^,_tr,i^o→w) by Δ_o^wΦ_i° = -(ΔG°^,_tr,i^o→w/z_iF) (z_i, the ionic valence), is important for understanding the distribution behaviors of ions for ion-selective electrodes, solvent extraction, membrane transport, etc. In this review, literature values of Δ_o^wΦ_i° have been compiled for various ions. A few topics relevant to Δ_o^wΦ_i° have also been addressed, which include new methods for the determination of Δ_o^wΦ_i° and a water | oil | water thermocouple for determination of the entropy of ion transfer at the oil/water interface.