基于纳米金／碳纳米管修饰石墨电极测定大黄酸

Determination of rhein based on nanogold / carbon nanotubes modified graphite electrode

本文首次采用自沉积方法将HAuCl4直接还原成纳米金颗粒并修饰在直接生长于石墨基体上的碳纳米管电极表面，制备了对大黄酸具有高催化性能的Au-CNTs／C电极。采用循环伏安法考察了大黄酸在Au—CNTs／C电极上的电化学行为，发现在-0．037V出现明显的氧化峰。在磷酸盐缓冲溶液P13S（DH=7．4）中，大黄酸的响应电流与浓度在1．8×10-4-2．5×10-3g／L范围内呈线性关系，相关系数为0．9878，其检测限为8．0×10^-4g／L。

In the paper, a novel Au-CNTs/C electrode behaving with electrocatalytic oxidation toward rhein is prepared firstly by auto-deposition of nanogold which is obtained by direct reduction of HAuCl4 onto the surface of the carbon nanotubes which grow on the graphite electrode directly. The electrochemical behavior of the modified electrode is studied by using a tri-electrode system with the modified electrode as working electrode, SCE as reference electrode and Pt-wire as counter electrode. It is found that, in phosphate buffer solution （pH=7.4）,a well-shaped redox peak of rhein is observed in -0.037V by cyclic-voltammetry and linear relationship is kept between Ipa and concentration of rhein in the range of 1.8×10-4-2.5×10-3g/1, with a correlation coefficient of 0.9878, the detection limit of this method is found to be 8.0 ×104g/1.