用甘氨酸对玻碳电极进行共价修饰用于多巴胺和抗坏血酸的伏安分离

Covalent modification of glassy carbon electrodes with glycine for voltammetric separation of dopamine and ascorbic acid.

作者信息

Zhang L, Lin X

机构信息

Department of Chemistry, University of Science and Technology of China, Hefei, Anhui.

出版信息

Fresenius J Anal Chem. 2001 Aug;370(7):956-62. doi: 10.1007/s002160100843.

DOI:10.1007/s002160100843

PMID:11569883

Abstract

Glycine was covalently grafted on to a glassy carbon electrode (GCE) by amine cation radical formation in electrooxidation of the amino-containing compound. X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry proved the immobilization of glycine on the GCE. The modified electrode reduced the overpotentials of dopamine (DA) and ascorbic acid (AA) by approximately 0.15 V and 0.23 V, respectively, and resolved the overlapping voltammetric response of DA and AA into two well-defined voltammetric peaks in cyclic voltammetry (CV) or differential pulse voltammetry (DPV), unlike the unmodified GCE; this can be used for the simultaneous determination of these species in a mixture. The differential pulse peak current was linearly dependent on DA and AA concentration in the range 5 x 10(-6)-8 x 10(-4) mol L(-1) and 6 x 10(-5)-4 x 10(-3) mol L(-1), with correlation coefficients of 0.996 and 0.994, respectively. The detection limits (3delta) for DA and AA were 1.8 x 10(-6) mol L(-1) and 2.1 x 10(-5) mol L(-1), respectively. The modified electrode is very sensitive, selective and stable, and has been applied to the determination of DA and AA simultaneously in samples with satisfactory results.

摘要

通过含氨基化合物的电氧化过程中胺阳离子自由基的形成，将甘氨酸共价接枝到玻碳电极（GCE）上。X射线光电子能谱（XPS）和循环伏安法证明了甘氨酸在GCE上的固定化。与未修饰的GCE不同，修饰电极分别将多巴胺（DA）和抗坏血酸（AA）的过电位降低了约0.15 V和0.23 V，并在循环伏安法（CV）或差分脉冲伏安法（DPV）中将DA和AA重叠的伏安响应解析为两个清晰定义的伏安峰；这可用于同时测定混合物中的这些物质。差分脉冲峰电流在5×10⁻⁶ - 8×10⁻⁴ mol L⁻¹和6×10⁻⁵ - 4×10⁻³ mol L⁻¹范围内分别与DA和AA浓度呈线性关系，相关系数分别为0.996和0.994。DA和AA的检测限（3δ）分别为1.8×10⁻⁶ mol L⁻¹和2.1×10⁻⁵ mol L⁻¹。修饰电极非常灵敏、选择性好且稳定，已应用于同时测定样品中的DA和AA，结果令人满意。