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Conventional Working Electrodes

A broad range of electrochemically active molecules can be detected with good to excellent sensitivity using one of several forms of electrochemical detection. These molecules include: carboxylic, sulfonic, and phosphonic acids; alcohols, glycols, aldehydes and carbohydrates; primary, secondary, tertiary and quaternary amines; sulfates, sulfoxides, thiols, sulfides, and mercaptans; and inorganic anions and cations. When compared to UV absorbance detection, electrochemical detection offers substantial improvements in sensitivity and selectivity for amine and hydroxy aromatics (catecholamines). Electrochemical detection also offers the advantage that carbohydrates can be detected without the derivatization required for fluorescence detection.

Before the introduction of disposable electrodes by Thermo Fisher Scientific, Conventional Working Electrodes (CWEs) were the standard used in electrochemical detection. CWEs consist of a rod of the electrode material (gold, silver, platinum or glassy carbon) embedded in a polymeric support.

When maintained properly, CWEs will last for extended periods of time, yielding consistent results and allowing the user the option to polish the electrode surface should the performance degrade over time, or when performance diminishes as a result of multiple analyses. These electrodes offer consistent results with very good lifetimes but sometimes require longer equilibration times once newly installed in a system. CWEs can offer excellent lifetimes if operated under recommended conditions and stored properly (in the shipping case) when not in use.

Thermo Fisher Scientific offers several choices of electrode products, including gold, platinum, silver and glassy carbon, which are all available in conventional formats.