4-dimethylaminobenzylamine as a sensitive chemiluminescence derivatizationreagent for 5-hydroxyindoles and its application to their quantification in human platelet-poor plasma

A selective and sensitive high-performance liquid chromatographic method wi th chemiluminescence detection for the determination of 5-hydroxyindoles is described, based on the reaction of 5-hydroxyindoles with 4-dimethylaminob enzylamine. Serotonin, 5-hydroxyindole-3-acetic acid, 5-hydroxytryptophol, 5-hydroxyindole-3-acetamide and N-acetyl-5-hydroxytryptamine were used as m odel compounds to optimize the derivatization and chemiluminescent reaction . The reagent reacts with 5-hydroxyindoles in slightly alkaline media in th e presence of potassium hexacyanoferrate(III) to give the corresponding der ivatives, which can be separated on a reversed-phase column, Wakosil-II 5C1 8RS, with aqueous acetonitrile as an eluent, The derivatives were detected by peroxyoxalate chemiluminescence detection. The detection limits are in t he range of 0.5-1.2 fmol per 100-mu l injection. The method was applied to the simultaneous determination of serotonin and 5-hydroxyindole-3-acetic ac id in human platelet-poor plasma. (C) 2000 Elsevier Science B.V. All rights reserved.