Zhang L, Lin X
Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
Analyst. 2001 Mar;126(3):367-70. doi: 10.1039/b009415n.
A novel covalently modified glassy carbon electrode with glutamic acid has been fabricated via an electrochemical oxidation procedure and was applied to the catalytic oxidation of uric acid (UA) and ascorbic acid (AA), reducing the overpotentials by about 0.2 V and 0.3 V, respectively. Based on its strong catalytic function toward the oxidation of UA and AA, the modified electrode resolved the overlapping voltammetric response of UA and AA into two well-defined voltammetric peaks with both cyclic voltammetry (CV) and 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 dependent on the UA and AA concentration in the range 2 x 10(-6)-4 x 10(-4) mol L-1 and 1.0 x 10(-6)-4 x 10(-4) mol L-1 with correlation coefficients of 0.996 and 0.997, respectively. The detection limits (3 delta) for UA and AA were 1.1 x 10(-6) mol L-1 and 9.2 x 10(-7) mol L-1, respectively. The modified electrode shows good sensitivity, selectivity and stability, and has been applied to the determination of UA and AA simultaneously in human urine samples with satisfactory results.
通过电化学氧化过程制备了一种新型的谷氨酸共价修饰玻碳电极，并将其应用于尿酸（UA）和抗坏血酸（AA）的催化氧化，分别使过电位降低了约0.2 V和0.3 V。基于其对UA和AA氧化的强催化作用，修饰电极通过循环伏安法（CV）和差分脉冲伏安法（DPV）将UA和AA重叠的伏安响应解析为两个清晰的伏安峰，可用于同时测定混合物中的这些物质。从DPV获得的催化峰电流在2×10⁻⁶ - 4×10⁻⁴ mol L⁻¹和1.0×10⁻⁶ - 4×10⁻⁴ mol L⁻¹范围内分别与UA和AA浓度呈线性关系，相关系数分别为0.996和0.997。UA和AA的检测限（3δ）分别为1.1×10⁻⁶ mol L⁻¹和9.2×10⁻⁷ mol L⁻¹。修饰电极具有良好的灵敏度、选择性和稳定性，并已应用于同时测定人尿液样本中的UA和AA，结果令人满意。
