A semi-mechanized method for the fluorometric determination of 5-hydroxytryptamine (serotonin) in blood plasma and platelets

1. 1. A description is given of a mechanized continuous flow system for the determination of serotonin in deproteinized plasma samples or platelet suspensions. 2. 2. The system consists of two extraction steps followed by the fluorometric assay of serotonin in the obtained final extract. 3. 3. There is no interference by related substances such as 5-hydroxytryptophan and 5-hydroxy-indole acetic acid. 4. 4. The reproducibility (standard deviation) of the method is within 3–5 ng/ml in the range of 250–750 ng added 5-hydroxytryptamine/ml plasma. 5. 5. The sensitivity allows the demonstration of less than 5 ng serotonin/ml aqueous solution.