Differential pulse techniques in weakly supported media: Changes in the kinetics and thermodynamics of electrode processes resulting from the supporting electrolyte concentration

Electrochemical analysis of anionic analytes in weakly supported media using electron transfer promotion effect: a case study on nitrite

In this study, a simple technique was developed for the electrochemical detection of anionic analytes in weakly supported media. This was conducted by the use of electrochemical paper-based analytical devices (ePADs). A sensing platform was modified with nereistoxin and used to determine nitrite as a case study. The electrochemical response was improved due to the accelerated electron transfer between the sensing platform and the nitrite through the electrostatic interaction of the amino group of nereistoxin and the nitrite. The electrocatalytic current of the nitrite in the presence of nereistoxin was enhanced in the weakly supported media. By using nereistoxin as a signal enhancer, 97% of the electrochemical signal was obtained at the low ionic strength of the electrolyte, while less than 35% of this signal was obtained in the absence of nereistoxin. The limit of detection was as low as 20 nM using an ePAD. Generally, the proposed ePAD serves as a promising, efficient and low-cost device for sensing applications in weakly supported media.

Recent Advances in Voltammetry

Recent progress in the theory and practice of voltammetry is surveyed and evaluated. The transformation over the last decade of the level of modelling and simulation of experiments has realised major advances such that electrochemical techniques can be fully developed and applied to real chemical problems of distinct complexity. This review focuses on the topic areas of: multistep electrochemical processes, voltammetry in ionic liquids, the development and interpretation of theories of electron transfer (Butler-Volmer and Marcus-Hush), advances in voltammetric pulse techniques, stochastic random walk models of diffusion, the influence of migration under conditions of low support, voltammetry at rough and porous electrodes, and nanoparticle electrochemistry. The review of the latter field encompasses both the study of nanoparticle-modified electrodes, including stripping voltammetry and the new technique of 'nano-impacts'.