SEROTONIN MONITORING IN MICRODIALYSATE FROM RAT-BRAIN BY MICROBORE LIQUID-CHROMATOGRAPHY WITH FLUORESCENCE DETECTION

A sensitive fluorimetric microbore-liquid chromatographic method for t he determination of serotonin in microdialysate from rat brain was dev eloped. The method is based on the fluorescence derivatization of sero tonin by reaction with benzylamine in the presence of potassium hexacy anoferrate(III). A microdialysis probe was implanted in the rat brain, and continuously perfused at 2.0 mu l min(-1) with Ringer solution. T he microdialysate, collected every 5 min, was added with a reagent sol ution composed of 0.3 M CAPS buffer (pH 12.0), 0.2 M benzylamine, 0.1 M potassium hexacyanoferrate(III) and methanol (1:1:5:10, v/v). The de rivatization reaction was completed by standing at room temperature fo r 2 min. The benzylamine derivative of serotonin could be separated wi thin 10 min on a reversed-phase microbore column (100x1.0 mm i.d., 5 m u m TSK gel ODS-80TM) with isocratic elution. The detection limit (sig nal-to-noise ratio=3) of serotonin is 80 amol for a 5 mu l injection. The effects of increased potassium ion concentration in the Ringer sol ution and a single intraperitoneal injection of methamphetamine on the serotonin level in microdialysate were examined, (C) 1998 Elsevier Sc ience B.V.