ELECTROCHEMICAL DETECTORS

The electrochemical detector is also a popular liquid chromatographic detector. It should be considered by the chromatographer because of the additional selectivity and sensitivity for some compounds.

This detector is based on the measurements of the current resulting from oxidation/reduction reaction of the analyte at a suitable electrode. Since the level of the current is directly proportional to the analyte concentration, this detector could be used for quantification..

The eluent should contain electrolyte and be electrically conductive. Most of the analytes to be successfully detected require the pH adjustments.

The areas of application of electrochemical detection are not large, but the compounds for which it does apply, represent some of the most important drug, pollutant and natural product classes. For these, the specificity, and sensitivity make it very useful for monitoring these compounds in complex matrices such as body fluids and natural products. Sensitivities for compounds such as phenol, catecholamines, nitrosamines, and organic acids are in the picomole (nanogram) range.

The purity of the eluent is very important, because the presence of oxygen, metal contamination and halides may cause significant background current and therefore, noise and drift in the base line.