Fluorimetric determination of biogenic 5-hydroxy- and 5-methoxyindoles by high-performance liquid chromatography using perchloric acid as post-column reagent.

A method for the determination of biogenic 5-hydroxy- and 5-methoxyindoles using high-performance liquid chromatography with fluorescence detection was developed. The specific fluorescence of these indoles induced by perchloric acid was utilized as the post-column detection system. The determination limits were 3 pmol for 5-hydroxy-L-tryptophan and 5 pmol for serotonin (5-HT) and 5-hydroxyindole-3-acetic acid (HIAA). The method was applied to the determination of 5-HT and HIAA in rat brain tissues using 5-hydroxygramine as the internal standard.