Determination of 6-hydroxy-1-methyl-1, 2, 3, 4-tetrahydro-β-carboline, 5-hydroxytryptamine and 5-hydroxyindole acetic acid in the neonatal rat brains using high performance liquid chromatography-electrochemical detection

A simple method was developed for the analysis of 6-hydroxy-l-methyl-l,2,3,4-tetrahydro-β-carboline (6-OH-MTHβC), 5-hydroxytryptamine (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) in rat brain by high performance liquid chromatography with electrochemical detection (HPLC-ECD). The separation of the sample was performed on a Discovery® HS F5 column (250 mm × 4.6 mm, 5 μm) with a mobile phase of the buffer (40 mmol/L citric acid + 20 mmol/L Na₂HPO₄ + 0.3 mmol/L EDTA₂Na, ph 4.0) -methanol (78: 22, v/v) at a flow rate of 1. 0 mL/min. The electrochemical detector was Coularray Detector-4. This method showed good linearity (r > 0.999 2) for the quantification of 6-OH-MTHβC, 5-HT and 5-HIAA in the concentration range of 1.0 - 500.0 μg/L. The limits of detection were 0.56, 0.26 and 0.53 μg/L, respectively. The recoveries of 6-OH-MTHβC, 5-HT and 5-HIAA spiked in rat brain samples were 87. 1% - 98.2%, 87.0% - 95.3%, 90.1% - 97.7%, respectively, and the relative standard deviations of intra-day and inter-day determinations were both less than 6. 1%. In comparison with the control, the analysis of alcohol-exposed neonatal rat brain samples revealed a significant difference in the level of 6-OH-MTHβC (P<0. 05). The method was proved to be simple, highly sensitive, and could be applied in the analysis of 6-OH-MTHβC, 5-HT and 5-HIAA in the rat brain.