分散铂聚苯胺修饰电极对肾上腺素电催化作用的研究

发布时间：2018-11-05 19:14

【摘要】： 肾上腺素(EP)是哺乳动物和人类的一种重要的神经递质,具有重要的生理功能,分析测定人体内肾上腺素的含量具有重要的意义。实验研究表明,导电聚合物聚苯胺(PAn)具有比表面积高、环境稳定性良好以及导电率高等特征,将其作为载体材料,沉积、分散具有催化活性的Pt金属,制备出分散铂聚苯胺修饰电极(Pt/PAn/GC)。本实验主要研究了Pt/PAn/GC电极对肾上腺素的催化作用以及影响该修饰电极催化活性的制备因素。本文选择EP为探针,分析影响铂在聚苯胺膜上电沉积的因素以及聚苯胺膜的厚度对修饰电极催化性能的影响,确定沉积铂的最佳条件为：掺杂酸为盐酸,其浓度为2.0mol／L、扫速50mV／s。采用循环伏安法研究了EP在分散铂聚苯胺修饰玻碳电极上pH=0.5的HCl介质、HClO4介质、H3PO4介质、HNO3介质、H2SO4介质、盐酸-氯化钾溶液、高氯酸-高氯酸钠溶液和硝酸-硝酸钾溶液中的电化学行为。实验结果表明,通过循环伏安扫描法制备的Pt/PAn/GC电极对肾上腺素有较好的催化性,与聚苯胺(PAn/GC)修饰电极和裸玻碳电极(GCE)相比,Pt/PAn/GC电极对EP具有更好的催化能力。通过改变不同的扫描速度,确定了扫速和氧化峰电流(ipa)的线性关系,说明肾上腺素在分散铂聚苯胺修饰电极上的电子转移过程受扩散控制。在1.5 mol/L的盐酸-氯化钾溶液中,氧化峰电流与EP的浓度在9.0×10-6 mol/L～2.5×10-3 mol/L范围内呈良好的线性关系,检出限为1.6×10-6 mol/L。可用于实际样品中EP的测定。采用交流阻抗法研究了分散铂聚苯胺修饰电极在盐酸溶液和盐酸-氯化钾溶液中的电化学行为。实验结果表明,随盐酸溶液浓度的增加,聚苯胺膜的电荷传递电阻越来越小,电荷的传递速度加快；研究了分散铂聚苯胺修饰电极、聚苯胺修饰电极和玻碳电极在盐酸-氯化钾溶液中的阻抗性能,结果表明,EP在聚苯胺修饰电极上的电氧化电阻比分散铂聚苯胺修饰电极上的大,分散铂聚苯胺修饰的电极可降低电极上EP氧化的电化学极化电阻。这与前面循环伏安法测得的结果一致。
[Abstract]:Epinephrine (EP) is an important neurotransmitter in mammals and humans and has important physiological functions. It is of great significance to analyze and determine the content of epinephrine in human body. The experimental results show that the conductive polymer Polyaniline (PAn) has the characteristics of high specific surface area, good environmental stability and high conductivity. It is used as the carrier material to deposit and disperse the Pt metal with catalytic activity. The dispersed platinum Polyaniline modified electrode (Pt/PAn/GC) was prepared. The catalytic effect of Pt/PAn/GC electrode on epinephrine and the preparation factors affecting the catalytic activity of the modified electrode were studied. In this paper, using EP as probe, the factors affecting the electrodeposition of platinum on Polyaniline film and the effect of the thickness of Polyaniline film on the catalytic performance of modified electrode are analyzed. The optimum conditions for platinum deposition are as follows: the doping acid is hydrochloric acid, the concentration is 2.0 mol / L, Sweep speed 50 MV / s. Cyclic voltammetry was used to study the HCl medium, HClO4 medium, H3PO4 medium, HNO3 medium, H2SO4 medium, hydrochloric acid-potassium chloride solution of pH=0.5 on the dispersible platinum Polyaniline modified glassy carbon electrode by cyclic voltammetry. Electrochemical behavior of perchloric acid-sodium perchlorate solution and nitric acid-potassium nitrate solution. The experimental results show that the Pt/PAn/GC electrode prepared by cyclic voltammetry has a good catalytic activity to epinephrine, compared with the (GCE) electrode modified by Polyaniline (PAn/GC) and the bare glassy carbon electrode. Pt/PAn/GC electrode has better catalytic ability to EP. The linear relationship between the scanning speed and the oxidation peak current (ipa) was determined by changing the different scanning rates. It was concluded that the electron transfer process of epinephrine at the dispersed platinum Polyaniline modified electrode was controlled by diffusion. In 1.5 mol/L hydrochloric acid-potassium chloride solution, the oxidation peak current showed a good linear relationship with the concentration of EP in the range of 9.0 脳 10-6 mol/L~2.5 脳 10-3 mol/L, and the detection limit was 1.6 脳 10-6 mol/L.. It can be used for the determination of EP in actual samples. The electrochemical behavior of dispersed platinum Polyaniline modified electrode in hydrochloric acid solution and hydrochloric acid-potassium chloride solution was studied by AC impedance method. The experimental results show that the charge transfer resistance of Polyaniline film decreases with the concentration of hydrochloric acid solution increasing, and the charge transfer rate increases. The impedance properties of dispersed platinum Polyaniline modified electrode, Polyaniline modified electrode and glassy carbon electrode in hydrochloric acid-potassium chloride solution were studied. The electrooxidation resistance of EP on Polyaniline modified electrode is larger than that on dispersed Platinum Polyaniline modified electrode, and the electrochemical polarization resistance of EP oxidation on the modified electrode can be reduced by dispersed platinum Polyaniline modified electrode. This is consistent with the results obtained by the previous cyclic voltammetry.
【学位授予单位】：曲阜师范大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：R341

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