title: Simultaneous analysis of dopamine and homovanillic acid by high-performance liquid chromatography with wall-jet/thin-layer electrochemical detection.
abstract: Wall-jet/thin-layer amperometric electrochemical detection (ECD) coupled with high-performance liquid chromatography (HPLC) was used here for the simultaneous analysis of dopamine (DA) and homovanillic acid (HVA) at a glassy carbon electrode. Compared with the conventional thin-layer mode and wall-jet mode, the presented wall-jet/thin-layer ECD has the advantages of enhanced capture of electroactive DA and HVA on the working electrode to give enhanced responses and more convenient washing/refreshment of the working electrode surface. Under optimized conditions, the HPLC-ECD calibration curves show good linearity from 0.01 to 100 μM for DA and HVA, and the limits of detection (LODs) obtained were 1.1 nM for DA and 0.7 nM for HVA which are lower than those obtained with an UV-vis detector and a commercial electrochemical detector. The method was tested on human urine with satisfactory results. The balance of response-signal, signal-background and noise level for our HPLC-ECD system is also discussed. In addition, a demethylation electrooxidation mechanism for HVA is suggested through potentiostatic bulk electrolysis, electrospray ionization-mass spectrometry, fluorescent spectrophotometry and cyclic voltammetry studies.
authors.affiliation: Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, P.R. China. xieqj@hunnu.edu.cn.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Zhou
authors.forename: Hongling
authors.initials: H
authors.lastname: Yan
authors.forename: Qingji
authors.initials: Q
authors.lastname: Xie
authors.forename: Siyu
authors.initials: S
authors.lastname: Huang
authors.forename: Jiali
authors.initials: J
authors.lastname: Liu
authors.forename: Zou
authors.initials: Z
authors.lastname: Li
authors.forename: Ming
authors.initials: M
authors.lastname: Ma
authors.forename: Shouzhuo
authors.initials: S
authors.lastname: Yao
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004298:Dopamine / Q000032:analysis*; D055664:Electrochemical Techniques / Q000379:methods*; D006719:Homovanillic Acid / Q000494:pharmacology*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D004298:Dopamine; D006719:Homovanillic Acid