A simple paired-ion liquid chromatography assay for serotonin in cerebrospinal fluid, platelet-rich plasma, serum and urine.

Anderson and co-workers recently described a simple high-performance liquid chromatographic/fluorimetric assay for serotonin and tryptophan, in which deproteinised samples were directly injected. Using this method routinely, we frequently observed interference which could not sufficiently be resolved from serotonin to allow accurate quantitation. However, when the amine was isolated by ion-exchange chromatography prior to HPLC separation as advocated by Koch and Kissinger, chromatograms were obtained with practically no extraneous peaks. In this paper the application of this method for the determination of serotonin in CSF, plasma, serum and urine is described.