3-巯基丙酸自组装金电极的制备及其对尿酸的电化学

Preparation of 3-mercaptoaceticpropionic acid self-assembled gold electrode and its electrochemical investigations for UA

采取自组装的方法制备3-巯基丙酸(3-mercaptoacetic propionic acid,MPA)自组装膜修饰金电极,进而采用循环伏安、交流阻抗等电化学方法对该电极进行表征,计算电极有效表面积为1.97×10-2 cm2.研究了尿酸(uricacid,UA)在该修饰电极上的电化学行为,结果表明,MPA/SAM/Au电极具有良好的稳定性和电化学活性,在pH=6.0的磷酸氢二钠-柠檬酸(Na2HPO4-C6H8O7)缓冲溶液中,相比裸金电极,MPA/SAM/Au电极对UA响应的峰电流较大.其氧化峰电流与尿酸的浓度在1.6×10-4～1×10-6 mol/L浓度范围内呈良好的线性关系,线性回归方程为ip/(μA)=0.738 9+0.040 46c0/(μmol/L),相关系数R=0.998 6,检测限为5×10-7 mol/L.

The 3-mercaptoaceticpropionic acid （MPA） self-assembled monolayers was prepared by immersing the bare gold electrode into the MPA solution for 24 h. The resulting substrates were characterized by Cyclic Voltammetry and EIS in [Fe（CN）6]^3-/4- solution and showed the MPA was attached on the gold electrode,and the effective surface area of the modified electrode was 1.97 × 10 2 cm2. Also, the result concluded that, in the pH = 6. 0 disodium phosphate-citric acid （Na2HPO4 - C6 H8 O7）buffer solution, the response of UA determined by the MPA/Au electrode was that the peak current was that higher and the peak potential shifted negatively, compared to the bare electrode and that the whole electrochemical process was controlled by diffusion. The concentration linearity was ip/ （uA）=0.738 9＋0. 0404 6c0/（umol/L）,R=0.998 6,in the solution range of 1.6X10 4 mol/L-1× 10^-6 mol/L and determined the sample UA. The proposed method was convenient and feasible with satisfactory result.