Electrochemistry at an interface between two immiscible electrolyte solutions (ITIES) offers a great opportunity to be applied to electroanalytical, biological and energy related research fields. In particular, ion transfer processes across a polarized ITIES have been employed as powerful electrochemical ion sensing platforms. This review will highlight recent developments in addition to some challenges and future aspects on developing ion selective sensing platforms utilizing ITIES specific to ionizable pharmaceutical reagents (drugs).

High-performance liquid chromatography with electrochemical detection (HPLC-ECD) by voltammetric oxidation on glassy carbon (GC) and boron-doped diamond (BDD) electrodes were performed to determine, respectively, attomole levels of catechins and femtomole levels of polymethoxyflavones. Also, these HPLC-ECD systems were applied to the analysis of green tea and Citrus depressa juice. The HPLC-ECD by voltammetric reduction on GC electrode was applicable to determine aristolochic acids in herbal medicine. Using a column-switching technique, three channel HPLC-ECD (3LC-ECD) has been developed for sensitive and simultaneous determination of phenolic acids (PHAs) and tanshinones (TANs) in Salvia miltiorrhiza. In 3LC-ECD using GC working electrodes, PHAs and TANs eluted from three columns were detected, respectively, at two oxidative (+0.7 V vs. Ag/AgCl) detection channels and at a reductive (–0.2 V vs. Ag/AgCl) detection channel. In conclusion, the present HPLC-ECD system has been characterized as a sensitive and selective analytical method for determining bioactive compounds derived from traditional Chinese medicines and plants.

Surface-enhanced infrared absorption spectroscopy with ATR configuration (ATR-SEIRAS) is a powerful tool for probing the electrochemical interface. Experimental details of this technique including know-how are described together with some outstanding results.

The mechanism of propagation or synchronization of self-sustained potential oscillations between two-membrane systems has been proposed. Two aqueous phases W1 and W1' were connected through common phases of nitrobenzene phase, O, and pure water phase, W2. It was demonstrated that the potential pulse was propagated together with an interfacial spreading of surface-active substance, and the accession of the pulse to another oscillation site induced the synchronized oscillation pulse. On the other hand, the faster propagation of the potential pulse was realized due to the interfacial blocking of the O/W2 interface, but the propagation due to the bulk conduction did not induce the synchronization of self-sustained oscillation.

Laplace transform was first introduced to electrochemistry in 1947 by Koutecký and Brdička, who derived an analytical equation of the polarographic “kinetic current” for weak acids at the dropping mercury electrode. Since then, Laplace transform has been successfully used to solve diffusion problems in a variety of electrochemical measurement systems. This article shows how to apply Laplace transform to obtain an analytical equation of the current–potential curve for a simple redox system. A previous practical application made by the author has also been described.