碳纳米管的氧化还原控制及其电化学检测多巴胺

摘要

Multi-wall carbon nanotubes ( MWCNTs) with different degrees of oxidation were prepared by a wet chemical oxida-tion method. Their morphology and chemical composition were characterized by infrared spectroscopy, X-ray photoelectron spec-troscopy and transmission electron microscopy. The oxidized MWCNTs were coated on glassy carbon for use as electrodes and their electrocatalytic oxidation activities for dopamine, ascorbic acid and uric acid were investigated by cyclic voltammetry and differential pulse voltammetry in order to evaluate their performance for selective dopamine detection. Results indicated that the electrocatalytic oxidation activities are dependent on both the electron transfer resistance of the graphitic layers and the electrostatic attraction between dopamine and carboxyl groups on the MWCNTs. Optimized MWCNTs with an appropriate content of carboxyl groups and nearly complete graphitic layers have a wide linear response current range for dopamine contents from 2 to 100μM, and can be used for the selective detection of dopamine in the presence of ascorbic acid and uric acid.%利用湿化学法制备出化程度不同的多壁碳纳米管，并采用红外光谱仪、X-射线光电子能谱仪、透射电子显微镜分析样品因氧化程度不同而引起的表面特征差异。通过循环伏安法和示差脉冲伏安法研究多巴胺，尿酸和抗坏血酸在氧化程度不同的碳纳米管修饰玻碳电极上的电化学行为。其中，样品MWNCTs-R修饰的玻碳电极与其它样品相比，不仅展现出对多巴胺，尿酸和抗坏血酸更好的电催化性能，而且解决了氧化峰相互重叠的问题，可以用于在尿酸和抗坏血酸共存的条件下检测多巴胺。同时，传感器的响应电流随着多巴胺含量的增加而线性增大，线性范围为2~100μM。结果表明，不同氧化程度导致碳纳米管表面的组成和形貌不同，表面含有羧基，并保持完整石墨层结构的碳纳米管对多巴胺有更好的电催化响应。