A liquid chromatographic assay for 5-hydroxytryptophan, serotonin and 5-hydroxyindoleacetic acid in human body fluids

We describe the precision and accuracy of a liquid chromatographic method, which uses internal standards, 6-fluoroserotonin and 5-hydroxyindolecarboxylic acid, in quantitating serotonin and 5-hydroxyindoleacetic acid in human cerebrospinal fluid, plasma and urine. In addition, 5-hydroxytryptophan is measured in the cerebrospinal fluid. The limit of sensitivity of this method is 0.1 pmol/injection, the peak height/concentration ratio is linear in the concentration range of 0.1 pmol to 50 mumol/injection, and the coefficient of variation is of the order of 15% at the limit of sensitivity and below 10% at amounts above 0.5 pmol/injection. No endogenous monoamines or their metabolites interfere with the quantitation of the substances of interest in the body fluids studied.