Anodic detection in flow-through cells

Abstract

Virtually all organic compounds and numerous inorganic compounds are predicted from thermodynamics to be oxidized at potentials accessible at commonly used solid electrodes in aqueous media by reactions which require transfer of oxygen from H₂O to the oxidation products. These anodic reactions are usually kinetically inhibited because of their complexity. Progress is summarized to develop electrocatalytic processes for anodic detection in flowing aqueous solutions.

Pulsed amperometric detection at Pt electrodes is applicable for the sensitive detection of the HCOH group in all alcohols, polyalcohols and carbohydrates, the nitrogen in amines, amino acids and aminoglycosides, and sulphur in most inorganic and organic compounds. Pure and doped lead dioxide electrodes are described for amperometric detection at constant potential.

The voltammetric response of electrocatalysed oxygen-transfer reactions is dictated by the potential dependence of the process transferring oxygen from H₂O to the electrode surface, so that attempts at voltammetric resolution of mixtures are not generally effective. The most useful analytical application of the electrocatalysed processes for mixtures is in the form of amperometric detection in liquid-chromatographic systems.