膜化学修饰电极的研究与应用

【作者】 贾晶晶；

【导师】 张国荣；

【作者基本信息】 山东师范大学 ， 分析化学， 2007， 硕士

【摘要】 化学修饰电极是当前电化学、电分析化学方面十分活跃的研究领域。目前已应用于生命科学、环境科学、分析科学、材料科学等方面。膜化学修饰电极是在电极表面进行分子设计，修饰在电极表面的媒介体可加速氧化还原中心在电极表面的电子传输过程以实现电催化反应。化学修饰电极广泛应用于难以实现电子转移的慢过程，例如：生物分子的电催化、无机粒子的电催化等。由于电极具有特定的化学和电化学性质，膜化学修饰电极大大地丰富了电化学的电极材料，拓宽了电化学的研究领域。聚合物膜含电活性中心浓度高，有三维可利用的势场，性能稳定，不溶或不熔且修饰方法简便，因此它一出现就迅速发展为化学修饰电极的研究重点。氨基酸是生物体的最基本的物质，又因含有氨基和羧基两种官能团而具有许多独特的性质，利用化学法或电话学法将氨基酸修饰到电极表面，在测定金属离子、生物分子、有机污染物等方面显示了其独特的优越性，得到了广泛的应用；自组装作为制备有机超膜的一种新型技术越来越受到广大学者的关注，在过去的几十年里，自组装膜（Self-assembled monolayer，SAMS）是构膜分子通过分子间及其与基体材料间的物理化学作用而自发形成的，是一种热力学稳定、排列规则有序的自组装膜。它具有均匀一致，高密堆积和低缺陷等特征，并能预先设计，通过精密的化学控制获得特定的功能；超分子的识别和催化作用是它的两个基本的性质，利用超分子的这两个性质将受体构筑成功能膜修饰在电极界面上，制成各种功能的修饰电极具有广阔的前景和实际意义。本文主要利用电化学聚合的修饰方法把特定的修饰体修饰到电极表面，制备了多种具有特定功能的修饰电极，研究了其电催化、选择、吸附富集等性能，并用于实际样品的分析测定。论文包括五部分工作：第一部分：制备了聚L-谷氨酸／铁氰根修饰电极，探讨了电极的制备与使用的最佳条件，研究了镉离子在该修饰电极上的电化学行为。实验表明：修饰电极在0.1mol／LHCl中对Cd²⁺有灵敏的伏安响应，线性范围4.0×10^-9～3.0×10^-5mol／L，检出险可达2.5×10^-9mol／L。第二部分：制备了聚L-组氨酸／铁氰根修饰电极，探讨了电极的制备与使用的最佳条件，研究了银离子在该修饰电极上的电化学行为，实验表明：在0.1mol／LHNO₃溶液中，修饰电极对Ag⁺有灵敏的电流响应，线性范围3.0×10^-12～7.0×10^-6mol／L，检测下限可达1.0×10^-13mol／L，用于测定水样中银的含量结果令人满意。第三部分：制备了聚甘氨酸／铁氰根修饰电极，探讨了电极的制备与使用的最佳条件，研究了铅离子在该修饰电极上的电化学行为，实验表明：在0.1mol／LHNO₃溶液中，修饰电极对pb²⁺有灵敏的电流响应，线性范围1.0×10^-9～7.0×10^-6mol／L，检测下限可达8.6×10^-10mol／L，用于水样中铅含量的测定，结果令人满意。第四部分：制备了聚苯丙氨酸／铁氰根修饰电极，探讨了电极的制备及使用的最佳条件，研究了抗坏血酸在该修饰电极上的电化学行为，实验表明：在pH5.6的PBS溶液中，修饰电极对Vc有良好的电化学响应，线性范围4.0×10^-7～2.0×10^-2mol／L，检测下限可达2.4×10^-7mol／L，用于Vc片中Vc含量的测定结果令人满意。第五部分：制备了聚组氨酸-镍复合膜电极，探讨了电极的制备与使用的最佳条件，利用Ni（Ⅲ）／Ni（Ⅱ）的强氧化性，研究了甲醛在该修饰电极上的电化学行为，实现了对水样中甲醛的测定。线性范围5.0×10^-7～2.0×10^-5mol／L，检测下限可达2.3×10^-8mol／L。更多还原

【Abstract】 Abstracts: The chemically-modified electrodes （CME） have been a most burgueoning and of the most flourish research realms in the electrochemistry and electroanalytic chemistry. It was for the moment widely appied in many case such as life sicence, envioronment sicence, energy source sicence, analytic sicence, electronics and meterial science. The film chemicaly modified electrodes are prepared by desigining the electrodes surface on the molecule level and immobilizing the molecules, ion and polymers of the specifically chemical and electrochemical functions. The mediator modified on the surface of electrode can accomplish the electrocatalytic reactions by accelerating electron transferring between redox centers and electrode surface. The eletrocatalysis of the modified electrode is an enormous impetus for its development and is widely used in the slow electron transferring processes, which isn’t easily realized, such as the electroanalysis of biomolecules, orgnic compounds and inognic ions. With specially chemical and electrochemical functions the modified electrode enriched the electrode materials and expanded the reseach fields of the electrochemistry.The preparations of the polymer films are very simple. The polymer film modified electrodes also have many other choiceness characters which have been widely synthesized; the polymer films usually have chemical, mechanical and electrochemical stability; the thickness of the film can be changed. So the polymer film modified electrode have very good development foreground on the application or research. Self-assembly as a new technique for the application of orgnic ultitrafilm was applied in various research fields by more and more investigations. Self-assembled monolayer （SAMS） is a kind of single molecular layer which deposited on the surface of the monolayer is that the molecules in the monolayer haxe a common direction, which is the molecules are well organized and oriented. It’s well know that calixarenes are a good group of cavity-shaped cyclic molecules comprising phonel units linked via alkylidene group. They process special cavity structure and thus are able to form host-guest inclusion complexes with a variety of molecules selectivity, if calixarenes weremodified on the electrode to form chemically membrance-modified electrodes, some molecules with electrochemical characters may be separated each other.In our papers, we made several modified electrodes with special functions by electrochemically polymerization, we also reseach the functions of these electrodes, such as the ability of electroanalyse, slection and adsorption. At the same time we use these modified electrode to determine the real products. The whole paper includes five parts,First, A new chemically modified GC electrode has been prepared by using polymeric L-giutamic acid/Fe （CN）₆^3- as a modifier. The best conditons of preparation and usation were studied. The result of the experiment shows that the midified electrode exerts an apparent catalytic effect on the cadmium （Ⅱ） oxidation. The stripping peak of cadmium （Ⅱ） ion on polymeric L-glutamic acid/Fe（CN）₆^3-/GC is proportional to concentration of cadmium（Ⅱ） ion between 4.0×10^-9～3.0×10^-5molL^-1. The detection limit is 2.5×10^-9molL^-1. The modified electrode was used to measure cadmium in water sample.Second, A new chemically modified GC electrode was prepared by using poly-L-histidine/Fe （CN）₆^3- as a modifier. The best conditions of preparation and usation were studied. The results of the experiment show that the modified electrode exerts an apparent catalytic effect on the silver （Ⅰ） ion. The oxidation stripping peak current increases linearly With the concentration of silver ion between 1.0×10^-12～5.0×10^-6molL^-1.The detection limit is 1.0×10^-13molL^-1. The modified electrode can be used to measure silver （I） ion in water.Third, A new Chemically modified glass carbon electrode has been prepared by using polyglycine/Fe（CN）₆^3- as a modifier, the electrochemical behaviors of lead （Ⅱ） ion on the modified electrode have been studied. A new approach is developed for sensitive and accurate determination of lead by the electrode. The stripping peak of lead （Ⅱ） ion on Polyglycine /Fe （CN）₆^3-/GC is proportional to concentration of lead （Ⅱ） ion between 1.0¹0^-9～7.0×10^-6molL^-1 and detection limit is 8.6x10^-10molL^-1.Forth, A new chemically modified GC electrode has been prepared by using polymeric L-phenylalanine acid/Fe（CN）₆^3- as a modifier, the electrochemical behaviors of Ascorbic acid （Vc） on the modified electrode have been studied. A new approach is developed for sensitive and accurate determination of Vc by the electrode. The peak of Vc on polymeric L-phenylalanine acid/Fe（CN）₆^3-/GC is proportional to concentration of Vc between 4.0×10^-7～2.0×10^-2molL^-1. The detection limit is 2.4×10^-7molL^-1. The modified electrode has been used to measure the effective content in pills of VcFifth, A polyhistidine-Ni film modified electrode has been prepared at bare GC, and its electrochemical behavior was studied by cyclic voltammetry. The experiments confirmed the electrochemical catalytic oxidation of formaldehyde on the modified electrode. Over the rang 5.0×10^-7～, 2.0×10^-5molL^-1, the oxidation peak currents are linearly proportional to the concentration of formaldehyde, the detection limit is 2.3×10^-8moiL^-1. The modified electrode can be used to measure formaldehyde in aqueous solution.更多还原