【作者】 梁瑞；

【导师】 赫春香；

【作者基本信息】 辽宁师范大学 ， 分析化学， 2011， 硕士

【摘要】 聚苯胺（PAn）原料廉价易得、合成简单、导电率高、稳定性好,一直是导电聚合物领域的研究热点。由于具有独特的掺杂行为和良好的电化学可逆性,所以在电分析化学领域已经进行了不少研究。多巴胺（DA）、尿酸（UA）、抗坏血酸（AA）均是存在于生命体内的小分子物质,分析体内这三种物质的含量具有重要的意义,三组分混合体系的电化学检测也一直是研究的热点之一。本文利用循环伏安法制备了聚苯胺修饰石墨电极,成功地实现了对DA、UA、AA的电化学区分,利用三组分的电催化氧化峰电流可实现三组分的同时检测。本论文主要开展了以下两方面的工作:1.采用电化学沉积的方法制备了聚苯胺修饰石墨（PAn/SG）电极,分析了苯胺在电极表面循环聚合的几个影响因素,实验结果表明最佳的聚合条件为:循环扫描的上限为+0.90 V,下限为-0.2 V,苯胺的浓度为0.020 mol/L,扫描周数为20周,扫描速度为0.05 V/s。通过改变不同的实验参数制得不同形貌的PAn膜,并通过循环伏安法、紫外光谱、扫描电镜对制得的PAn膜进行了表征,对反应机理进行了简单的探讨。该修饰电极能在空气中稳定存在。2.利用制备好的PAn/SG修饰电极,对多巴胺、尿酸、抗坏血酸的混合溶液进行同时测定。在0.5 mol/L的H2SO4溶液中,三者的氧化峰得到了很好的分离,多巴胺和尿酸之间的峰电位差为110 mV,多巴胺和抗坏血酸之间的峰电位差为250 mV。而且在一定的浓度范围内,三者的氧化峰电流各自与其浓度呈良好的线性关系,可实现三组分体系中任一成分的测定,重现性较好,检出限分别如下:DA是1.00×10^-5 mol/L,UA是1.10×10^-5 mol/L,AA是2.00×10^-5 mol/L。采用循环伏安等技术研究了三组分的可逆性、吸附性,以及转移的电子数和参与反应的质子数,推测出各自的电极反应机理。更多还原

【Abstract】 Polyaniline （PAn） has attracted considerable interesting due to its availability, simple synthesis, high conductivity and stability. Because Polyaniline film has a unique doping behavior and good electrochemical reversibility,a lot of research of PAn-film modified eleetrode in the analysis and testing has been conducted. Dopamine （DA）、uric acid （UA）、ascorbic acid （AA） are small molecules of life that present in the body,it is significant to analysis these three substances, the electrochemical detection of three mixed systems has also been one of the hot. In this paper, a polyaniline modified graphite electrodes was prepared by cyelic voltammetry, the peak potential of dopamine、uric acid and ascorbic acid were separate on the modified electrode, and can achieve simultaneous detection of three components.This paper mainly carried out the following two aspects:1. A new electrode of polyaniline modified graphite was prepared by electrochemical deposition, several factors affecting the polymerization of aniline on the electrode surface have been investigated. the experimental results showed that the best polymerization conditions are: the upper scanning potential of cyclic voltammetry is 0.95 V, the lower scanning potential is -0.2 V, the concentration of aniline is 0.020 mol/L, the scan weeks are 20, scanning rate is 0.05 V/s. Different PAn films were obtained by varying the experimental parameters, characterized them by cyclic voltammetry, UV, scanning electron microscopy and discuss the reaction mechanism simplely. The modified electrode can be stable in the air.2. Determinating the mixed solution of dopamine, uric acid, ascorbic acid by PAn / SG modified electrode. In the solution of 0.5 mol/L vitriol,the peak potential of these there component were separated on the electrode, the potential difference between dopamine and uric acid is 110 mV, the potential difference between dopamine and ascorbic acid is 250 mV. Their peck current was linear respond to their concentration. The detection limits are as follows: DA is1.00×10^-5 mol/L,UA is 1.10×10^-5 mol/L,AA is 2.00×10^-5 mol/L. Discuss the reversible、adsorption、the electrons of transfered and the protons in the responses of three components by Cyclic voltammetry technique.更多还原