[Development of a liquid chromatography/multiple electrochemical detector (LCMC) and its application in neuroscience]

A liquid chromatographic system with multiple electrochemical detectors (LCMC) was newly developed for quantitating 20 to 30 neurochemicals simultaneously within 20 to 25 min from one sample derived from biological specimens. The device can be used for estimating neurofunctional changes in the central nervous system under the influence of CNS drugs, behavioral changes of experimental animals and psychic effects in clinical stages, etc. The system consists of four parallel liquid chromatographs with multiple electrochemical detectors. The first three systems determine catecholamines, indoleamines and related compounds. The fourth system is for measuring acetylcholine and choline with an internal standard. A new type of electrochemical detector was developed that consists of 4 electrodes set at a different potentials: each of the eluting components was identified by the variation of 4 current peaks on each electrode. Twenty-eight standard compounds, including four internal standards, could be clearly separated; and the detection limits of these compounds were at least 0.1 to 0.4 pmol per injection. In this report, the usefulness and applicability of this system were confirmed by measuring neurochemicals in the striatum of rats sacrificed either by decapitation or microwave irradiation and in the human ventricular cerebrospinal fluid of patients with Parkinson's disease and essential tremor.