Sub-Picogram Determination of Serotonin Using HPLC with Electrochemical Detection for Microdialysis Studies of Serotonin Release

The technique of microdialysis offers a unique avenue for monitoring extracellular chemical dynamics in nervous tissue. In using this technique to monitor neurotransmitters with high affinity uptake systems, the accurate determination of the extremely small amounts of material recovered represents an analytical challenge. For determinations of serotonin (5-HT) in microdialysis perfusates, HPLC coupled with either fluorescence (Kalen et al., 1988), or electrochemical (Brazell et al., 1985; Sharp et al., 1986) detection has been employed. Both means of detection offer high sensitivity and selectivity. This manuscript presents a Chromatographic system we have designed and constructed which offers extremely high sensitivity, suitable for analysis of microdialysis perfusates. In addition, the cost of the components for this system are roughly an order of magnitude less than the cost of a commercial system. The essential components are a pneumatic displacement fluid pump, narrow bore HPLC column, and battery-powered potentiostat for the electrochemical detection of 5-HT.