【作者】 肖素芳；

【导师】 王宗花；

【作者基本信息】 青岛大学 ， 应用化学， 2004， 硕士

【摘要】 碳纳米管（CNT）独特的一维分子结构和奇特的物理、化学特性，成为世界范围内的研究热点之一。相对于其它的领域，CNT在分析化学中的应用研究起步较晚。本论文把这种新型的纳米材料用作修饰电极的界面材料，率先研究了它的电催化、电分离以及复合环糊精之后的分子认知功能。本工作对于进一步开拓纳米材料的应用基础研究具有较大的意义。 本论文的工作分为四大部分： 一、CNT涂层修饰电极（CNT/E）对神经递质的电分离及同时测定。 以多巴胺（DA）和肾上腺素（EP）为模型化合物，研究其在多壁碳纳米管（MWNT）修饰电极上的直接电化学行为。结果表明，CNT/E对DA和EP的电化学行为有显著的增敏和电分离作用，还原峰电位差达△E_pc=390 mV，且性能稳定，利用DA和EP在修饰电极上阴极化过程峰电位的差异，实现了在AA共存时DA和EP的选择性测定。 二、以超分子环糊精对CNT进行功能化，构置环糊精复合碳纳米管功能化电极（CD／CNT／CE）。 CD水溶液对碳管有较好的‘溶解’行为。电镜（包括SEM和TEM）和FTIR表征，证实CD成功的系在了碳管表面或固定在集合孔中，显示了电极表面的微观形貌为立体的多孔界面层。碳管表面与环糊精之间的作用力为疏水的相互作用、范德华力以及空间阻力。 碳纳米管与超分子结合，增加CNT的可溶性，优化修饰电极的性能。界面体现了新颖的建筑层—碳纳米管集合体大的孔隙充填小孔的环糊精，将碳纳米管的优良催化性能和CD的认知包络行为结合起来。 三、CD／CNT／CE对生物分子、异构体的电分离、识别功能和选择性灵敏测定。 1．研究AA在CD／CNT／CE的电化学行为，探讨采用不同碳纳米管生物兼容性的界面，对电活性物质电化学行为的影响。经碳纳米管修饰的电极可降低AA的氧化反应的过电势，复合α-CD后可显著提高AA的灵敏度，更重要的是可避免DA的干扰。氧化处理CNT，对分析测定AA是一不利因素。 2．α-CD／CNT复合电极对CySH有较强的电催化行为，解决了电极对CySH氧化产物吸附而导致的信号逐渐减小的问题，实现了对L-CySH选择性灵敏测定。 3．以邻、间、对位硝基酚异构体为模型化合物，研究了各种CD／CNT／CE对硝基酚异构体的电催化行为及分子识别能力。摘要 4.研究了两嗓吟碱基一一A和G在p一CD功能化碳纳米管修饰电极的电化学 氧化行为。利用p一cD/C NT尼实现了对A和G的高灵敏度选择性测定，并 进行了酸变性鱼精子DNA中A和G组分的检测。本工作为免标记研究 DNA杂交行为及其与小分子的相互作用提供了有效途径。 四、CNT修饰电极的电催化、电分离及识别机理。 CNT修饰电极优异的性能来源于碳纳米管的纳米尺寸、一维管状结构、电子特性及其集合体的立体空间结构;CNT修饰电极的立体界面孔性是对生物分子产生电化学催化的重要原因。CD附着在CNT表面，增加了修饰电极的分子识别能力。更多还原

【Abstract】 Studies on carbon nanotubes (CNT) become a hot topic in the world due to the unique one-dimensional tubular structure and subtle physical and chemical properties of CNT. Compared with other area, the application of CNT in analytical chemistry has been studied recently. In the present dissertation, using CNT as interfacial material, the functionalized CNT electrodes were constructed; the electrocatalysis and separation of CNT-modified electrodes and its recognition ability after incorporating cyclodextrins (CD) were studied firstly. This work may be of great signification for applying nano-material further. The main achievements obtained in this research include:1. CNT-coated electrode was constructed with CNT as electrode material for the electro-separation and simultaneous detection of neurotransmitters.The electrochemical characteristics of dopamine (DA) and epinephrine (EP) at multi-wall carbon nanotube coated graphite electrode have been investigated. The result demonstrated that the modified electrode shows enhanced sensitivity and excellent electrochemical discrimination to DA and EP, the cathodic potential difference of DA and EP was about 390 mV. DA and EP can be determined simultaneously in the presence of AA by their cathodic potential difference.2. CNT was functionalized successfully with supermolecular CD and further CD incorporating CNT modified electrodes (CD/CNT/CE) were constructed and characterizedCD solution has good dispersion behavior towards CNT. By SEM, TEM and FTIR characterization, we testified that CDs were adsorbed and attached to the surface of CNT due to hydrophobic interaction, van der Waals force and steric effect. It also shows the stereo-porous interface structure of electrode surface.CD can attach to the surface of CNT, which can enhance the solubility of CNT and be favorable to the properties of modified electrode. With the CD-CNT adduct, a novel interface architecture of electrode was constructed and it was characterized by a large aggregated pore of carbon nanotube captured CD with a small cavity. The perfect electrocatalytic properties of CNT coupled with the specific recognition properties of CD would indeed make for an ideal sensor.3. The voltammetric separation and recognition ability of CD/CNT/E for biomolecules and isomers were investigated systematically.(1). The electrochemical response of AA on CD/CNT/CE was investigated. The influence of different biocompatibility interfaces to electroactive analyte was discussed further. Modification of the electrode surface by carbon nanotubes reduced the overpotential for the redox process, and significantly increased the sensitivity of AA by incorporated a-CD. More importantly, the interference of DA can be avoided. Experiment results indicated that the oxidation treatment of CNT was unfavorable to the detection of AA.(2). a-CD/CNT/E exhibits perfect eletrocatalytic ability to CySH, which resolved the problem of electrochemical response reducing gradually due to oxidation products adsorption. The selective and sensitive determination of CySH was obtained.(3). Using neutral nitrophenol isomers as model compounds, the eletrocatalytic response and recognition ability of various cyclodextrins-incorporated carbon nanotube electrodes were firstly investigated and characterized systematically.(4). The electrochemical oxidation response of adenine and guanine on B-CD functionalized CNT modified electrode was described. The selective and sensitive determination of A and G was obtained and further estimate the contents of A and G in denaturing herring sperm DNA. Our work provides available approach to the amplified label-free electrochemical detection of DNA hybridization and the interaction with targeted agents.4. The electrocatalysis, separation and recognition mechanism of CNT modified electrode were investigated.The results suggest that the pronounced properties of CNT modified electrode come from its nano-dimension, subtle tubule structure and the spatial porous interfacial of aggregated更多还原