Development of a High-Performance Liquid Chromatography System with Multi-Electrode Electrochemical Detectors for Determination of Levels of Neurotransmitters in Cerebrospinal Fluid

Abstract

We have developed an HPLC system for the simultaneous determination of neurotransmitters such as catecholamines, serotonin, and their precursors and metabolites. This system consists of two reversed-phase columns, a column switching device, a pair of electrodes for elimination of interferents and two sets of new electrochemical detectors with four electrodes. Using this system, adequate separation of peaks for 17 kinds of neurotransmitters in a standard solution required only 17 min. Norepinephrine (NE), 4-hydroxy-3-methoxyphenylethyleneglycol (MHPG), 3, 4-dihydroxyphenylacetic acid (DOPAC), 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA) and tryptophan (TRP) levels in cerebrospinal fluid (CSF) were determined without any pretreatment of CSF samples. The between-day CVs were less than 5% for all analytes in CSF. The analytical rates of recoveries were between 91 and 101%. CSF samples from patients with Alzheimer's disease, vascular dementia and Parkinson's disease were analyzed, and it was found that the concentrations of DOPAC, 5-HIAA and HVA were significantly lower in CSF of patients with these diseases than in CSF of the age-matched controls.