Amperometric determination of (R)-salsolinol, (R)-N-methylsalsolinol and monoamine neurotransmitters with liquid chromatography using functionalized multi-wall carbon nanotube modified electrode in Parkinson's patients' cerebrospinal fluid

The fabrication and application of a novel electrochemical detection (ED) system with the functionalized multi-wall carbon nanotubes (MWNTs) chemically modified electrode (CME) for liquid chromatography (LC) were described. The electrochemical behaviors of dopamine (DA) at the CME were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). It was found that the CME exhibited efficiently electrocatalytic effect on the current responses of (R)-salsolinol ((R)-Sal), (R)-N-methylsalsolinol ((R)-NMSal), and monoamine neurotransmitters with high sensitivity, stability, and long-life of activity. In LC-ED, all (R)-Sal, (R)-NMSal, DA, norepinephrine (NE), 3-methoxy-4-hydroxyphenylglycol (MHPG), 3,4-dihydroxyphenylacetic acid (DOPAC), 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), and homovanillic acid (HVA) had good and stable current responses at the CME. The linear ranges of the nine analytes were over three orders of magnitude (R-2 > 0.995). The application of this method coupled with microdialysis sampling for the determination of (R)-Sal, (R)-NMSal, and monoamine neurotransmitters in Parkinson's patients' cerebrospinal fluid was satisfactory. (C) 2004 Elsevier B.V. All rights reserved.