碳原子线修饰电极对肾上腺素及尿酸的电催化作用

发布时间：2018-01-14 18:30

本文关键词：碳原子线修饰电极对肾上腺素及尿酸的电催化作用　出处：《南京师范大学》2006年硕士论文　论文类型：学位论文

【摘要】：本文报告碳原子线(carbon atom wires，简写为CAWs)修饰电极对肾上腺素和尿酸的电催化作用。肾上腺素和尿酸是人体内的生理活性物质，研究它们的电化学反应对深入研究生命科学和医药科学具有十分重要的意义。利用循环伏安法、紫外可见吸收光谱法和强制对流法研究了肾上腺素在碳原子线修饰电极上的电化学行为和反应机理。与裸玻碳电极相比，硝酸处理的碳原子线修饰玻碳电极在含有1mmol／L肾上腺素的0.5mol／L H_2SO_4水溶液中的循环伏安曲线上的氧化峰电位E_(pa)负移87mV，还原峰电位E_(pc)正移139mV，氧化峰电流i_(pa)和还原峰电流i_(pa)分别增加5.6倍和16.4倍。由强制对流法测得，在0.5mol／L H_2SO_4水溶液中、硝酸处理过的碳原子线修饰电极上，肾上腺素氧化成肾上腺素醌的异相电子传递标准速率常数k~0相对于裸电极增大16倍，这些结果表明碳原子线对于肾上腺素的电极过程具有非常高的电催化活性。通过循环伏安法结合紫外可见吸收光谱研究了肾上腺素的电极过程的反应机理。结果表明，肾上腺素的氧化还原过程比较复杂，在反应过程中除了电极上的多步电子转移外，还伴随有化学反应，并且在一些反应步骤中有H~+的参与，因此，，肾上腺素的循环伏安曲线上的电化学响应与扫描速率及介质的pH值密切相关。碳原子线修饰电极上的肾上腺素的循环伏安实验还表明，其氧化还原峰电流与其浓度在1×10~(-4)～1×10~(-2)mol／L范围内成线性关系，因此碳原子线修饰电极可用于肾上腺素的电分析，检测限为2×10~(6)mol／L。本文利用差分脉冲伏安法研究了尿酸在不同电解质溶液中的电化学行为，显示碳原子线修饰电极对尿酸的电化学过程具有很好的催化作用。此外，本文还研究了pH在碳原子线修饰电极对尿酸电催化作用过程中的影响，结果表明，在pH=4～9的范围内，氧化峰电位E_(pa)与pH成线性关系，其线性方程的斜率表明，在该电极反应过程中有相同数目的质子和电子参与电极反应。由实验还测得，碳原子线修饰电极的氧化峰电流与扫描速率的平方根成正比，说明该电极反应受扩散控制。
[Abstract]:In this paper, atom wires of carbon atom is reported. The electrocatalytic action of modified electrodes on adrenaline and uric acid. Epinephrine and uric acid are physiological active substances in human body. The study of their electrochemical reactions is of great significance for the further study of life sciences and medical sciences. The electrochemical behavior and reaction mechanism of epinephrine on carbon atomic line modified electrode were studied by cyclic voltammetry, UV-Vis absorption spectroscopy and forced convection. Oxidation peak potential on cyclic voltammetry curves in 0.5 mol / L H _ 2SO _ 4 aqueous solution containing 1 mmol / L epinephrine on nitric acid treated carbon wire modified glassy carbon electrode. Negative shift 87mV. The reduction peak potential (ESP) was positively shifted to 139mV, the oxidation peak current was increased by 5.6 times and the reduction peak current by 16.4 times by forced convection method. In 0.5 mol / L H _ 2SO _ 4 aqueous solution, the carbon atom line modified electrode was treated with nitric acid. The standard rate constant of heterogeneous electron transfer of epinephrine to adrenerone was 16 times higher than that of bare electrode. These results indicate that carbon atomic lines have very high electrocatalytic activity for the electrode process of epinephrine. The reaction mechanism of the electrode process of epinephrine has been studied by cyclic voltammetry and UV-Vis absorption spectra. To show. The redox process of epinephrine is quite complex. In addition to the multi-step electron transfer on the electrode, there are also chemical reactions in the reaction process. The electrochemical response on the cyclic voltammetry curve of epinephrine is closely related to the scanning rate and pH value of the medium, and the cyclic voltammetry of epinephrine on the carbon atom line modified electrode also shows. The redox peak current is linearly related to the concentration in the range of 1 脳 10 ~ (-1) ~ (-2) mol / L, so the carbon atom line modified electrode can be used for the electrical analysis of epinephrine. The detection limit is 2 脳 10 ~ (10) mol 路L ~ (-1). The electrochemical behavior of uric acid in different electrolyte solutions has been studied by differential pulse voltammetry. The results show that the carbon atom line modified electrode has a good catalytic effect on the electrochemical process of uric acid. The effect of pH on the electrocatalysis of uric acid by carbon atomic wire modified electrode was also studied. The results showed that the oxidation peak potential (EPS) was linearly related to pH in the range of pH=4~9. The slope of the linear equation shows that the same number of protons and electrons participate in the electrode reaction. The oxidation peak current of the modified electrode is proportional to the square root of the scanning rate, which indicates that the electrode reaction is controlled by diffusion.
【学位授予单位】：南京师范大学
【学位级别】：硕士
【学位授予年份】：2006
【分类号】：R341

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