修饰电极的制备及对亚硝酸盐等小分子的检测及杀菌性能的研究

【作者】 陈全鹏；

【导师】 艾仕云；

【作者基本信息】 山东农业大学 ， 环境工程， 2010， 硕士

【摘要】 当今,环境污染的程度逐渐增大,直接影响到人们正常的生产和生活,甚至威胁到人类的生存,环境保护形势日益严峻。因此,开发能够持续、快速、有效的检测并消除污染的手段和方法势在必行。而化学修饰电极以其廉价、快速、灵敏度高、选择性好等优点,较好的迎合了现阶段环境分析任务的要求,受到了广泛的关注。纳米材料独特的结构状态使其产生了小尺寸效应、量子尺寸效应、表面效应等,从而在光、电、吸附、催化等方面展现出独特的功能。利用纳米材料对基底电极进行修饰时,电极表面比表面积急剧增大,这就为电极的进一步修饰或对被测物的检测提供了更多的活性位点。另外,纳米材料修饰电极时,其本身的物化特性也被引入电极表面,从而使得该电极的电化学活性得到强化。本文研究了纳米材料修饰电极对生物大分子的作用及其在环境污染物分析中的应用,主要分为以下四个方面：1.通过将醛基二茂铁与第3代树状高分子复合制备了末端为二茂铁的树状大分子(Fc-D),并以Nafion溶液为固定剂用以修饰玻碳电极。研究结果表明该修饰电极对神经递质多巴胺的氧化还原具有较强的催化作用,对多巴胺的检测具有较高的灵敏度和较好的线性范围,并且能够有效的排除抗坏血酸的影响。2.以第4代树状高分子、多壁碳纳米管和壳聚糖复合材料修饰玻碳电极,并分别采用共价键结合和静电吸附法,以戊二醛和DNA为交联剂固定细胞色素C构建了新型亚硝酸盐生物传感器。结果表明,该纳米复合材料非常适合作为细胞色素C的固定材料,并具有较高的催化活性,被固定的细胞色素C的电化学响应十分明显。利用该生物传感器对亚硝酸盐检测的响应速度快,灵敏度高,线性范围宽,检出限低,并具有较强的抗干扰能力和良好的稳定性与重现性。3.在离子液体与水的两相溶液中,通过电沉积的方法制备了纳米二氧化铅修饰的钛电极,以此电极为阳极,探讨了该电极对水体中细菌的杀灭能力。对比实验与死亡细胞的透射电镜图表明,在灭菌过程中起主要作用的是电生成的羟基自由基。另外,随着离子液体含量的增加,电沉积的二氧化铅的粒径逐渐减小。较小的粒子赋予了电极较大的比表面积和更多的活性位点,能够生成更多的羟基自由基,并最终使得杀菌效果逐步增大。4.首先制备了层间插入十二烷基磺酸钠的镁铝类水滑石,然后在十六烷基三甲基溴化铵和3-氨丙基三乙氧基硅烷的作用下使其氨基化制备了氨基化镁铝类水滑石(NH2-HTlc)。然后以NH2-HTlc为修饰剂修饰热解石墨电极,并通过循环伏安法探讨了该电极对吸附在其表面的大肠杆菌的杀灭作用。结果表明,被吸附的大肠杆菌在经过循环伏安扫描后死亡率达到了98.68%,大肠杆菌的死亡可归因于其内部鸟嘌呤的氧化。更多还原

【Abstract】 In recent years, with the increasing of its degree, environmental pollution has directly affected people’s normal production and life, and even threats human survival. The environmental protection situation becomes worse and worse. Therefore, it is imperative to develop the sustained, rapid and effective means for the detection and elimination of pollution. The chemically modified electrode with its advantages such as cheap, fast, high sensitivity and good selectivity, better meet the mission requirements of current environmental analysis, and receives more and more attention.Owing to the small size effect, quantum size effects, surface effects resulted from its unique structure, nano-materials have shown distinctive function in many fields such as optical, electronic, adsorption, catalysis and so on. By using of the nano-materials modified electrode, the electrode surface increases rapidly, which would provide more active sites for the further modification. In addition, when the nano-materials were used to modify electrode, both of their own physical and chemical properties had also been introduced to the electrode surface, and the electrochemical active of the electrode would be greatly strengthened. In this paper, we have studied the effect of the nano-materials modified electrode to the biological macromolecules and the environmental pollutants, which could be divided into four aspects as follow:1. Ferrocenyl-tethered PAMAM G3 dendrimers (Fc-D) was synthesized and used to modified glassy carbon electrode (GCE) with Nafion acting as the binder. The obtained modified electrode had a dramatically enhanced electrocatalytic property to DA and effectively eliminated the interference of AA. The proposed method showed a high sensitivity and a good linear range.2. Novel nitrite biosensors were successfully prepared via immobilizing Cytochrome c (Cty c) onto the multi-walled carbon nanotubes-PAMAM-chitosan (MWNT-PAMAM-Chit) nanocomposite modified glass carbon electrode (GCE), with glutaraldehyde and DNA acting as the coupling agent, respectively. The results showed that MWNT-PAMAM-Chit nanocomposite provided a perfect platform for the immobilization of Cyt c and facilitates the electron exchange between the Cyt c and electrode. The immobilized Cyt c displayed a good electrocatalytic response to the oxidation of nitrite, which was attributed to the highly reactive Cyt c 7r-cation generated by the further oxidation of Cyt c. The obtained novel nitrite biosensors exhibited wide linear ranges, low detection limit, good reproducibility and stability.3. The electrochemical inactivation of microorganisms using Escherichia coli (E. coli) as testing species by a novel PbO2 electrode was investigated. The PbO2 electrode was constructed by electrochemical deposition of PbO2 on the treated Ti substrate in the fluorine (F) doped ionic liquids/water (ILs/H2O) two phase solution. Further investigation showed that the crystal size of electrodeposited PbO2 became smaller with the increase of ILs concentration in the electrolyte solution. The small crystal size favored to the generation of the absorbable·OH on the electrode surface, which was proved to play a key role during the disinfection process. TEM investigation revealed the morphological change of the E. coli cells during the bactericidal process.4. The surfaces of the interlayer of MgAl-hydrotalcite like compounds (MgAl-HTlc) have been modified with amine moieties through condensation between the hydroxyl groups and APS molecules, forming a covalent bond. Then, it was used to modify graphite electrode for the adsorption of E. coli. Cyclic voltammetry (CV) was used to investigate the disinfection of the modified electrode. The result showed that the germicidal efficiency could reach to 98.68% and the possible disinfection mechanism might be the oxidation of guanine within E. coli.更多还原