Detection and identification modes for the highly sensitive and simultaneous determination of various biogenic amines by coulometric high-performance liquid chromatography.

Detection and identification modes for the rapid, selective, highly sensitive and simultaneous determination of catecholamines, indoleamines and related metabolites by high-performance liquid chromatography (HPLC) with series of coulometric working electrodes (CWE) were investigated. Five detection modes were examined: (1) oxidative single mode using a single CWE, (2) oxidative screen mode using a series of two CWE, (3) redox mode using a series of two CWE, (4) redox-reductive screen mode using a series of three CWE and (5) redox-reductive screen mode using a series of four CWE. For the highly sensitive detection of catechol compounds, oxidative single, redox and redox-reductive screen modes were suitable. Oxidative single and oxidative screen modes were better than the other modes for indole and o-methylated catechol compounds. For the selective detection of these compounds, however, the redox-reductive screen mode was best. The specific ratio obtained in HPLC with the redox or redox-reductive screen mode is useful as an index for identification purposes. These findings suggest that HPLC with the redox-reductive screen mode of detection is applicable to neuroscience studies.