Determination of picogram levels of brain serotonin by a simplified liquid chromatographic electrochemical detection assay.

A simplified assay is described for measurement of picogram amounts of serotonin (5-HT) by high pressure liquid chromatography with electrochemical detection (LCEC). The procedure involves pre-purification of brain 5-HT by adsorption on Amberlite CG-50. Serotonin is subsequently resolved and detected by LCEC on Zipax SCX resin. The present method gives working sensitivities of at least 100 pg, tissue recoveries of 95% and very low interassay variability (coefficient of variation = 3%). Determination of rat brain area 5-HT by this LCEC method is described and compared to other high sensitivity methods.