【作者】 王淑敏；

【导师】 屈建莹；

【作者基本信息】 河南大学 ， 分析化学， 2008， 硕士

【摘要】 本文对化学修饰电极的类型、制备方法以及其应用价值,尤其是在分析化学中的应用作了比较详细的评述,在此基础上,以碳纳米管、4-氨基苯甲酸、巯基乙酸、铁氰化物等修饰材料在电极表面构建新的界面,并对它们的电化学性质和应用进行了研究。主要内容如下:1.多壁碳纳米管修饰玻碳电极伏安法测定氯霉素将纯化后的碳纳米管分散于无水乙醇中,并以此为修饰剂,制备出相应的修饰电极,研究了氯霉素(CAP)在该修饰电极上的电化学行为,发现在pH = 2.0的0.1 mol/L KCl-HCl底液中,CAP在该修饰电极上有一灵敏的还原峰(Ep = -0.36 V vs.Ag/AgCl),峰电流与CAP浓度成正比,线性范围为6.0×10-6 ~ 2.7×10-4 mol/L,检测限达3.0×10-6 mol/L。该方法灵敏、准确,用于模拟样品和实际样品的测定,结果满意。2.铁氰化物膜在巯基乙酸修饰金电极上的制备及其在电分析化学中的应用研究通过层层组装的方法,将金属盐(Ni2+、Co2+)和[Fe(CN)6]3-交替沉积在巯基乙酸功能化的金电极表面。制备了铁氰化物多层膜修饰电极,用循环伏安法研究了该多层膜的电化学行为,结果表明膜均匀增长,峰电流随膜层数的增加而增加。该修饰电极对一价金属离子Na+,K+和NH4+具有选择性响应,尤其对K+存在准能斯特响应;而且对抗坏血酸和S2O32-体系的氧化具有良好的电催化作用。所制备的电极均具有良好的稳定性。3.亚甲基蓝和纳米金共修饰电极的研制及其对甲醛的电催化氧化在玻碳电极上共价键合一层4-氨基苯甲酸,构建负电荷界面,然后通过静电作用沉积一层阳离子电子媒介体亚甲基蓝(MB),再通过金?硫、金?氮共价键合作用和静电吸附作用自组装一层纳米金(nano-Au),由此制备了纳米金/亚甲基蓝/4-氨基苯甲酸修饰电极(nano-Au/MB/4-ABA/GC)。在碱性介质中,该电极对甲醛有较好的催化氧化作用,使甲醛在+0.13 V和+0.28 V处出现两个氧化峰,可以根据+0.13 V处的氧化峰测定甲醛的含量,该法测定甲醛的线性范围为10 ~ 125 mg/L,检出限0.5 mg/L。更多还原

【Abstract】 This article described in detail the types, preparation methods and applicable value of modified electrodes, especially in the field of analytical chemistry. Using functional material like carbon nanotubes, 4-Aminobenzoic acid, mercaptoacetic acid, metal hexacyanoferrates etc. as the modified agents, new interfaces were constructed at the electrode surface. Electrochemical behaviors and their applications of the resulting modified electrodes were studied. The main research work was as follows:1. Voltammetric determination of chloramphenicol using glassy carbon electrode modified with multi-wall carbon nanotubesCarbon nanotube was purified and dispersed in anhydrous alcohol, then as the modified material, it was dipped on the glassy carbon electrode to prepare chemical modified electrode. A sensitive electrochemical method was developed for determination of chloramphenicol (CAP) using a glassy carbon electrode modified with multi-wall carbon nanotubes (MWNTs) film. In 0.1 mol/L KCl-HCl solution of pH 2.0. A sensitive cathodic peak of CAP on the MWNTs modified electrode was obtained at around -0.36 V (vs. Ag/AgCl). Under the optimum conditions, the reduction peak current was linearly proportional with the concentration of CAP over the range of 6.0×10-6 to 2.7×10-4 mol/L with a detection limit of 3.0×10-6 mol/L. The proposed method is sensitive and accurate, and can be applied to determine CAP in simulated samples and real samples with satisfactory results.2. Assembly of metal hexacyanoferrates films immobilized on mercaptoacetic acid modified gold electrode and their applications in electroanalytical chemistry An electroactive metal hexacyanoferrates (MHCF, M=Ni2+ or Co2+) films through layer-by-layer assembly based on electrostatic attraction on the mercaptoacetic acid (MA) modified gold electrode. Experiments showed that the modified electrode exhibited selected response to these ions and exhibited a near-Nernstian response to K+. What’s more, it could catalyze the oxidation of AA and S2O32- in KCl solution. All these electrodes prepared exhibited good stability.3. Electrocatalytic oxidation of formaldehyde on methylene blue and nano-Au modified glassy carbon electrode4-Aminobenzoic acid (4?ABA) was covalently grafted on a glassy carbon electrode (GCE) to form a negatively charged surface, and cationic methylene blue was linked by electrostatic adsorption as an electron transfer mediator. The nano-Au was assembled on the electrode was linked by Au?S and Au?N covalent bond and electrostratic adsorption. The electrode had better catalytic oxidation to the formaldehyde (HCHO) in the alkalinemedia. The HCHO appeared two oxidation peaks at +0.13 V and +0.28 V, the former oxidation peak used to determine the concentration of HCHO range of 10 ~ 125 mg/L with a detection limit of 0.5 mg/L.更多还原