Review—Voltammetric Sensors with Laterally Placed Working Electrodes: A Review

Abstract

Voltammetric sensors with laterally placed working electrode are an interesting alternative to classic electrodes since they offer enhanced performance in electroanalysis. Their characteristics include easier preparation for measurement, removal of interferences and gas bubbles, amplification of mass-transport, and possibility of miniaturization and automation. In this review, construction and characteristics of the custom-designed in our team cyclically renewable, silver, gold, bismuth, glassy carbon, ceramic and amalgam annular band, bi-band, ring, and multidisc electrodes are discussed in detail. They represent the current trends in electroanalysis, aimed at reducing of amount of the used toxic electrode materials, like mercury and its compounds, and organic solvents used for a sample preparation, and are coherent with the concept of Green Chemistry. For each sensor type available strategies for mechanical and electrochemical surface renovation/activation before measurement are elucidated and evaluated on the basis of interpretation of voltammetric and tensammetric curves. Particular attention is put on electrochemical characteristics of the described sensors and their application for determination of trace amounts of metal ions and their complexes, organic compounds, and surface-active substances by means of tensammetry, and anodic, cathodic, adsorptive and catalytic adsorptive stripping voltammetry. Final considerations are addressed to the possibility of measurement automation and related future prospects.

Recent Progress in Electrochemical Immunosensors

“…In voltammetric immunosensors, the current is obtained from the analyte measurements when the potential is changed. The potential between the working and reference electrodes changes over time, and the current generated between the working and counter electrodes vi the electrochemical reaction of the analytes is measured [23]. The signal originates from the oxidoreduction processes at the surface of the working electrode, caused by the electroactive species.…”

Hexagonal cobalt oxide nanosheet-based enzymeless electrochemical uric acid sensor with improved sensitivity

“…This was due to the increase in the film thickness, which resulted in the reduction of the electron transfer rate and a decrease in conductivity. 31,32 Fig. 2 FESEM images at different resolution (a-c) and the XRD pattern (d) of the as-synthesised hexagonal shaped cobalt oxide nanosheets.…”

Electrochemical stripping analysis

“…Before each measurement, the electrode is cleaned and activated 227 . Electrochemical cleaning, which involves cycling the potential or holding the potential at a judiciously selected predetermined value for a defined period of time, can be used to condition the electrode surface 225,228 .…”