【作者】 罗培丽；

【导师】 冶保献；

【作者基本信息】 郑州大学 ， 环境科学， 2013， 硕士

【摘要】 化学修饰电极,作为电分析化学领域最重要的工具,在提高电极的选择性和灵敏度方面有其独特的优越性。目前,化学修饰电极已广泛应用于分析科学、生命科学、环境科学和材料学等诸多领域。随着纳米材料的发展,将纳米材料应用到化学修饰电极领域,进一步改善了电极的工作性能。当采用纳米材料修饰电极时,不仅引入了纳米材料本身的优越性能,增大了电极的比表面积和导电性,还对某些测定物质具有电催化效应。本文以碳纳米管和纳米金为修饰材料,并结合L-半胱氨酸的优点构筑了几种伏安传感器,其主要研究工作如下：1.采用滴涂法制备了MWCNTs-Nafion复合膜修饰电极,并用该修饰电极研究了尼泊金甲酯的电化学氧化过程。结果显示该修饰电极对尼泊金甲酯有良好的电化学响应和电催化性能。在最优的条件下,测定尼泊金甲酯的线性范围为3.0×10-6mol L-1～1.0×10-4molL-1,检出限为1.0×10-6molL-1。此外,还把构筑的修饰电极用于化妆品中尼泊金甲酯含量的测定,得到满意的结果。2.采用电聚合的方法制备了聚L-半胱氨酸修饰玻碳电极,并用循环伏安和交流阻抗法对其进行了表征。研究了日落黄在该修饰电极上的电化学行为。优化了实验条件,并建立相应的分析方法。在最佳实验条件下,日落黄的浓度与峰电流在8.0×10-9～7.0×10-7mol L-1之间呈线性关系,检出限为4.0×10-9molL-1。在3.0×10-7molL-1柠檬黄存在的情况下,日落黄检测的线性范围为1.0×10-8～5.0×10-7mol L-1,检出限为6.0×10-9mol L-1。将该修饰电极用于饮料中日落黄含量的测定,与紫外可见光谱法测定的结果一致。3.利用滴涂法和自组装技术结合制备了Nano-Au/L-cys/MWCNTs-Nafion/GCE,构筑这种新型伏安传感器用于沙丁胺醇的检测。实验表明该传感器显著提高了沙丁胺醇的氧化峰电流,通过一系列电化学手段对沙丁胺醇的电化学氧化行为进行了研究,并计算了相应的电极反应过程动力学参数。在最佳测定条件下,沙丁胺醇检测的线性范围为2.0×10-7～7.0×10-6mol L"1,检出限为9.0×10-8mol L-1。更多还原

【Abstract】 Chemically modified electrodes (CMEs), the most important tool in electroanalytical chemistry, show the unique advantages in selectivity and sensitivity. It has been widely applied in analytical science, life science, environmental science, materials science and other fields. With the development of nanomaterials, it is widely used for developing CMEs and can further improve the performance of electrode. Nanomaterials, due to their unique properties, have attracted much attention in the field of electrochemical sensor. Nanomaterials can not only increase surface area and conductivity of modified electrodes, but also show catalytic effect toward some anlyte. In this thesis, we fabricated some modified electrodes based on muti-walled carbon nanotubes, gold nanoparticles and L-cysteine. The main results are expressed as follows:1. A novel voltammetric sensor using multi-wall carbon nanotubes (MWCNTs) coupled with Nafion modified glassy carbon electrode (GCE) was developed for the detection of methylparaben (MP). This sensor exhibited good electrocatalytic activity toward the oxidation of MP in the phosphate buffer solution (PBS, pH6.5). Under the optimum conditions, the anodic peak currents of MP were linearly relationship with MP concentrations in the range of3.0×10"6mol L’1-1.0x10-4mol L-1. The detection limit was1.0×10-6mol L-1. The proposed method was successfully applied to determine MP in cosmetic with satisfactory results.2. A glassy carbon electrode was modified with L-cysteine by cyclic voltammetry. The modified electrode was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), and used as a voltammetric sensor in detecting Sunset Yellow. Under the optimum experimental conditions, the modified electrode showed a linear voltammetric response for Sunset Yellow in the range of8.0x10’9～7.0×10-7mol L-1with a detection limit of4.0x10-9mol L"1. Under the presence of3.0×10’7mol L"1tartrazine, the linear relationship between peak current and concentration of sunset yellow was1.0x10-8～5.0x10"7mol L"1, with a detection limit of6.0x10-9mol L-1. The method was applied successfully to detect Sunset Yellow in a drink sample, and provided the same analytical result as the UV reference method.3. A novel voltammetric sensor for Salbutamol was fabricated via the self-assembly of L-cysteine and Nano-Au on MWCNTs-Nafion-membrane. This sensor exhibited excellent activity toward the oxidation of Salbutamol. The electrochemical behaviors of Salbutamol were investigated and some kinetic parameters were calculated using various electrochemical techniques. Under selective conditions, the detect linear range was2.0x10"7～7.0x10-6mol L-1with a detection limit of9.0×-8mol L-1更多还原