【作者】 向翠丽；

【导师】 费锡明；

【作者基本信息】 华中师范大学 ， 物理化学， 2006， 硕士

【摘要】 化学修饰电极是当前电化学和电分析化学学科十分活跃的研究领域,它通过共价、键合、吸附或聚合等手段,将具有功能性的物质引入电极表面,制得具有新的、特定功能的电极,这种特定功能使电极能进行所期望的选择性反应,并加快反应速度,提高分析测定灵敏度,因而在分析测试中具有广阔的应用前景。 Nation修饰电极属于离子型聚合物修饰电极,它是将Nafion涂于电极表面制成的具有很强离子交换能力的修饰电极。Nafion修饰电极具有富集、电催化和选择性透过的特性。广泛应用于伏安分析、传感器、电催化分析和色谱分析等分析化学领域,且分析测定范围愈来愈广。本文在前人研究的基础上,制备了Nafion膜修饰玻碳电极,将其应用于测定水样中的微量铟和锡,同时本文首次将多壁碳纳米管与Nafion膜同时修饰在玻碳电极上制成复合电极测定了药物中的左旋多巴,进一步推广了Nafion膜修饰电极在电分析化学中的应用。论文主要内容包括以下几个方面: 1.制备了Nafion膜修饰电极,比较了修饰电极与裸玻碳电极在分析检测上的性能优劣,进一步推广了修饰电极在电化学测量中的应用。 2.用Nafion膜修饰玻碳电极测量了水样中的痕量铟,采用阳极溶出伏安法,研究了In（Ⅲ）在Nafion修饰电极上的伏安行为和测定的最佳化条件。该法简便快速,灵敏度高,选择性好,而且可以有效的消除汞污染。在pH=5.0的0.01 mol/L的NaAc-HAc缓冲溶液中,峰电流In（Ⅲ）浓度在1×10^-9～1×10^-7mol/L范围呈良好的线性关系,检测限为7.5×10^-10mol/L。该法用于实际水样中痕量铟的测定,结果满意,平均回收率为98.431%。 3.利用Nafion修饰玻碳电极测定痕量锡,采用阳极溶出伏安法,在所选的最优化实验条件下,峰电流与Sn（Ⅳ）浓度在1×10^-9～1×10^-7mol/L的范围呈良好的线性关系,检测限为2.46×10^-10mol/L。该法用于实际水样中痕量锡的测定,平均回收率为97.24%。 4.制备了多壁碳纳米管-Nafion膜复合修饰电极,并用此电极测定了生物活性分子左旋多巴,在所选实验条件下峰电流与L-dopa浓度在3.5×10^-7-1.5×10^-5mol/L的浓度范围呈良好的线性关系,检测限为5.0×10^-8mol/L。该方法灵敏度高,准确性好,设备简便,线性范围宽,检测限低,是一种新颖的测定L-dopa的电化学方法。更多还原

【Abstract】 Recently, chemically modified electrodes （CMEs） have been given highly investigations in the fields of electrochemistry and electroanalytical chemistry. Through various methods such as covalence, adsorption, polymerization, some specific electrocatalytic substances are modified onto the surface of the naked electrodes to fabricate the CMEs which make the electrochemical reactions to the desired directions. The CMEs have so many advantages including high sensitivity, relative simplicity and low cost of equipment that they are dramatically applied to the analytical detections.The Nafion polymer is chemically inert, noneletroactive, hydrophilic and insoluble in water and thus possesses almost ideal properties for preparation of modified electrodes. The CME tends to exclude anionic and neutral interferences .On the basis of previous study, Nafion modified glassy carbon electrode was fabricated used for determination of trace indium and tin in the water samples by the adsorption stripping voltammetry （ASV） .Besides, a novel multi-walled carbon nanotubes （MWNTs）- Nafion modified glassy carbon electrode was also fabricated for the A method for determination of L-Dopa which is one of the most important catecholamines. The main researches were summarized as follows:1. A Nafion modified glassy carbon electrode （NMGCE） is fabricated, and its advantages were given intensive studies.2. A new method for determination of trace indium is proposed by the adsorption stripping voltammetry （ASV） using a Nafion modified glassy carbon electrode. This chemically modified electrode （CME） shows a better stability. A sensitive oxidation peak was observed and the anodic peak potential is ca.-0.548V （vs. SCE）. The influences of various experimental parameters on the current peak were completely studied. Under the optimized condition, the method has been applied to the determination of indium in water samples. There is a good linear relationship between the peak current （i_p） and indium （Ⅲ） concentration in the range of 1.0×10^-91.0×10^-7mol/L and the limit of detection is 7.5×10^-10 mol/L.3. An application of using a Nafion modified glassy carbon electrode to detect trace tin by Voltammetry is reported. The experimental conditions have been optimized. Thepeak current is proportional to the concentration of tin in the range of lxlO"9 ^lxlO"7mol/L, and the limit of detection is 2.46xlO"10 mol/L. The method has been applied to the determination of tin in water samples and the average recovery is 97.24%.4. A method for determination of L-Dopa is proposed by the adsorption stripping voltammetry （ASV） using a multi-walled carbon nanotubes （MWNTs）- Nafion modified glassy carbon electrode （GMGCE）. This chemically modified electrode （CME） shows a better stability. A sensitive oxidation peak was observed and the anodic peak potential is ca.0.374V （vs. SCE）. The influences of various experimental parameters on the current peak were completely studied. Under the optimized condition, the method has been applied to the determination of L-dopa in samples. There is a good linear relationship between the peak current （ip） and L-dopa concentration in the range of 3.5xlO"7 ¹.5xlO"5 mol/L* with the limit of detection is 5.0xl0"8 mol/L,更多还原