Simple and rapid determination of serotonin and catecholamines in biological tissue using high-performance liquid chromatography with electrochemical detection

Using the CNS of Lymnaea stagnalis a method is described for the rapid analysis of neurotransmitters and their metabolites using high performance liquid chromatography coupled with electrochemical detection. Tissue samples were homogenised in ice-cold 0.1 M perchloric acid and centrifuged. Using a C18 microbore column the mobile phase was maintained at a flow rate of 100 μl/min and consisted of sodium citrate buffer (pH 3.2)-acetonitrile (82.5:17.5, v/v) with 2 mM decane-sulfonic acid sodium salt. The potential was set at +750 mV versus Ag|AgCl reference electrode at a sensitivity of 50 nA full scale deflection. The detection limit for serotonin was 11.86 ng ml−1 for a 5 μl injection. Preparation of tissue samples in mobile phase reduced the response to dopamine and serotonin compared with perchloric acid. In addition it was found that the storage of tissue samples at −20 °C caused losses of dopamine and serotonin. As a result of optimising the sample preparation and mobile phase the total time of analysis was substantially reduced resulting in a sample preparation and assay time of 15-20 min.