Chen Po-Yen, Vittal R, Nien Po-Chin, Ho Kuo-Chuan
Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan.
Biosens Bioelectron. 2009 Aug 15;24(12):3504-9. doi: 10.1016/j.bios.2009.05.003. Epub 2009 May 13.
Glassy carbon (GC) electrode was modified using multi-wall carbon nanotubes (MWCNTs), quercetin (Q) and Nafion in this sequence. The thus modified electrode was used for the detection of dopamine (DA) in the presence of equimolar ascorbic acid (AA). It is demonstrated in this study that MWCNTs can increase the current response of DA by five-fold and Q can reduce the oxidation overpotential of DA by about 60 mV, compared to these parameters obtained with a bare GC electrode. It is also shown that a layer of Nafion can virtually eliminate the interference of AA for the detection of DA. The GC/MWCNTs/Q/Nafion electrode (hereafter also called composite electrode) shows a current density of about 900 microA cm(-2) for DA, compared to the value of 80 microA cm(-2) of the GC electrode and to the value of 390 microA cm(-2) of the GC/MWCNTs electrode. The 11-fold enhancement in the sensitivity of the GC electrode for DA determination is attributed to the composite modification of the electrode, and is substantiated through various cyclic voltammetric experiments. Cyclic voltammetry (CV) and linear sweep voltammetry were used to characterize the electrodes. Calibration curves of batch and flow systems were obtained by amperometry for the detection of DA. Additionally, the composite modified electrode was tested with a human serum sample for the determination of DA and was found to be promising at our preliminary experiments.
玻碳（GC）电极按此顺序用多壁碳纳米管（MWCNTs）、槲皮素（Q）和Nafion进行修饰。如此修饰后的电极用于在等摩尔抗坏血酸（AA）存在下检测多巴胺（DA）。本研究表明，与裸GC电极相比，MWCNTs可使DA的电流响应增加五倍，Q可使DA的氧化过电位降低约60 mV。还表明，一层Nafion实际上可以消除AA对DA检测的干扰。GC/MWCNTs/Q/Nafion电极（以下也称为复合电极）对DA的电流密度约为900 μA cm⁻²，相比之下，GC电极的值为80 μA cm⁻²，GC/MWCNTs电极的值为390 μA cm⁻²。GC电极用于DA测定的灵敏度提高了11倍归因于电极的复合修饰，并通过各种循环伏安实验得到证实。采用循环伏安法（CV）和线性扫描伏安法对电极进行表征。通过安培法获得批处理和流动系统的校准曲线以检测DA。此外，用复合修饰电极对人血清样品进行DA测定测试，在我们的初步实验中发现很有前景。
