Covalent Modification of Glassy Carbon Electrodes with β-Alanine for Voltammetric Separation of Dopamine and Ascorbic Acid
Covalent Modification of Glassy Carbon Electrodes with β-Alanine for Voltammetric Separation of Dopamine and Ascorbic Acid
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DOI：
10.2116/analsci.17.939
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发表时间：
2001-08
影响因子：
1.6
通讯作者：
Lei Zhang;Yu-Gang Sun
中科院分区：
文献类型：
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作者：
Lei Zhang;Yu-Gang Sun
在玻碳电极（GCE）上，通过在含氨基化合物的电氧化过程中形成胺阳离子自由基，将β -丙氨酸共价接枝到玻碳电极上。X射线光电子能谱（XPS）和循环伏安法（CV）证明了β -丙氨酸单分子膜在GCE上的固定化。该电极对多巴胺（DA）和抗坏血酸（AA）表现出较强的电催化作用，过电位分别降低了0.20 V和0.23 V。由于其对DA和AA的催化作用不同，该修饰电极可将DA和AA的重叠伏安响应分解为两个明确的伏安峰，可用于混合物中DA和AA的同时测定。DA和AA的浓度分别在4.0 × 10^-6 ~ 5.0 × 10^-4 mol/L和2.0 × 10 ^-5 ~ 6.0 × 10 ^-3 mol/L范围内与峰电流呈良好的线性关系，相关系数分别为0.997和0.995。DA和AA的检出限（3 σ）分别为2.4 × 10^-6 mol/L和1.2 × 10 ^-5 mol/L。该电极具有良好的灵敏度、选择性和稳定性，用于样品中DA和AA的同时测定，结果满意。
β -Alanine was covalently grafted on a glassy carbon electrode (GCE) by amine cation radical formation in the electrooxidation process of the amino-containing compound. X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) proved the immobilization of β -alanine monolayer on GCE. The electrode shows strong electrocatalytic functions to dopamine (DA) and ascorbic acid (AA), reducing the overpotentials by 0.20 V and 0.23 V, respectively. Due to its different catalytic effects toward DA and AA, the modified electrode resolved the overlapping voltammetric responses of DA and AA into two well-defined voltammetric peaks by CV or differential pulse voltammetry (DPV), which can be used for the simultaneous determination of these species in a mixture. The catalytic peak current obtained from DPV was linearly related to DA and AA concentrations in the ranges of 4.0 × 10^-6 - 5.0 × 10^–4 mol/L and 2.0 × 10–^5-6.0 × 10–^3 mol/L with correlation coefficients of 0.997 and 0.995, respectively. The detection limits (3 σ ) for DA and AA were 2.4 × 10^-6 mol/L and 1.2 × 10–^5 mol/L, respectively. The electrode shows good sensitivity, selectivity and stability, and has been applied to the determination of DA and AA simultaneously in samples with satisfactory results.