Detection and identification modes for the highly sensitive and simultaneous determination of various biogenic amines...

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.