【作者】 杨冬旭；

【导师】 朱连德；

【作者基本信息】 东北师范大学 ， 分析化学， 2009， 硕士

【摘要】 本论文主要研究了典型偶氮化合物——苏丹红I号在碳纳米管膜修饰电极上的电化学行为,建立了一种高灵敏度的测定苏丹红I号的方法,并且对苏丹红I号在碳纳米管膜修饰电极上的电化学反应机理进行了详细的研究。本文的具体研究分为以下两个部分:(1)对比玻碳电极研究了苏丹红I号在碳纳米管膜修饰电极表面的氧化行为,证明碳纳米管对苏丹红I号在电极上的氧化具有极高的催化能力。详细考查了包括溶液pH值、极化电位等影响催化氧化响应的因素,得到了该修饰电极催化氧化苏丹红I号的最佳实验条件,并以此为基础建立了一种灵敏度(21.56μA mM-1)高,选择性好,线性范围(1.01×10-6—1.22×10-4 M)宽,检出限(12.7μM)低的测定苏丹红I号的方法。而且,该修饰电极对于苏丹红I号的测定具有很好的稳定性,能够显著降低电极的钝化程度。(2)通过循环伏安法、恒电位电解等电化学手段,并辅以紫外-可见光谱法等光学手段详细的研究了苏丹红I号偶氮(─N=N─)基团在碳纳米管膜修饰电极上的电化学反应过程。计算出了参加反应的电子数及质子数,以及溶液中发生的均相化学反应的动力学常数。通过实验现象的总结和数据的处理得到了苏丹红I号在碳纳米管膜修饰电极上的电化学反应机理:根据溶液pH值的不同苏丹红I号的反应经历两个不同的过程,它们在电极反应步骤、参与反应的电子和质子数及反应产物方面都有明显的区别。此前,从未有关于苏丹红I号的电化学反应机理研究的报道。更多还原

【Abstract】 In this dissertation, a multiwall carbon nanotubes (MWCNT) modified glassy carbon electrode (GCE) was prepared by casting MWCNT suspension on the surface of the GCE. Evaporation of solvent from such a solution yielded robust surface film contained MWCNT. The MWCNT/GCE can greatly catalyze the oxidation of–OH in Sudan I. Consequently, an amperometric sensor for Sudan I was proposed. The amperometric sensor has excellent performance associated with high sensitivity (21.56μA mM-1), low detection limit (3.46×10-8 M) and wide linear range (1.01×10-6~1.22×10-4 M). The MWCNT/GCE can also minimize the fouling effect of the electrode surface and showed very good short-time stabilityAdditionally, the electrochemical reaction mechanism of Sudan I has been investigated at the MWCNT modified GCE (MWCNT/GCE) in phosphate buffer solution (PBS) with various pH values. Cyclic voltammetry, controlled-potential electrolysis and UV-vis spectrophotometry studies showed that the reduction of–N=N– group in Sudan I yields aniline andα-amino naphthol through the intermediate product hydrazo. The whole reaction processes were proved to be the ECE mechanism. When the pH was above 5, another process took place and the ultimate products were same as in acidic solution.更多还原