A column chromatographic method for the determination of 5-hydroxytryptamine (serotonin) and 5-hydroxyindole acetic acid in cerebrospinal fluid.

A method is described for measurement of 5-hydroxytryptamine (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) in cerebrospinal fluid. 5-HT and 5-HIAA are isolated from columns of Biorex BR-70 and Sephadex G-10 with recoveries of 85 and 89% respectively. The indoles are quantitated by fluorometric measurement of the ortho-phthaldialdehyde derivatives in acidic solution. Correction for interfering 5-methoxytryptamine and 5-methoxyindole acetic acid is accomplished by a second measurement at alkaline pH. Thin-layer chromatographic analysis of column eluates has revealed no other interfering indoles in the 5-HT and 5-HIAA fractions. Preliminary results in normal cerebrospinal fluid samples have been in the ranges 10--60 ng/ml 5-HIAA and 0--13 ng/ml 5-HT.