【作者】 刘静；

【导师】 施汉昌； 周小红；

【作者基本信息】 清华大学 ， 环境工程， 2012， 硕士

【摘要】 自1990s以来，微电极开始在环境领域中逐渐得到了应用，成为表征液/固界面微环境特征参数浓度变化梯度的有力工具，为研究液/固界面的微观传质过程和反应动力学原理提供了重要的手段。近年来，纳米科学技术迅速发展及其在微电极领域的应用，促进了新型的传感器的研究。本论文针对传统复合式溶解氧微电极，对其结构进行优化，以工作电极柱表面镀银作为保护阴极，简化了电极制作过程，使电极拉制成功率得到了提高。对其检测特性的测试结果表明，新型溶解氧微电极的保护阴极可以使电极的残余电流降低约60%，在300pA左右；线性相关性R2都在0.99以上；保护阴极的存在可以使电信号的输出更加稳定，扰动影响从3%~4%降低至0.5%左右，对溶解氧浓度的分辨能力约0.4mg/L。采用低温水热法实现氧化锌纳米棒在铂电极表面的沉积，通过静电吸附在氧化锌纳米棒表面固定葡萄糖氧化酶。成功制备的修饰纳米氧化锌葡萄糖氧化酶微电极尖端直径小于10μm，响应时间在0.5s以内，最低检测限为2mmol/L，线性范围为4mmol/L~30mmol/L，葡萄糖溶液浓度与响应峰电流的线性相关性系数达到了0.9973。同时，利用电沉积方法在碳纤维基底电极上修饰纳米金颗粒，并交联固定葡萄糖氧化酶。制备纳米金修饰的葡萄糖氧化酶微电极尖端直径约为30μm，响应时间在1s以内，最低检测限为1mmol/L，线性范围为1mmol/L~20mmol/L，葡萄糖溶液浓度与响应峰电流的线性相关性系数为0.9471。最后对两种葡萄糖氧化酶微电极从基底电极材料、修饰情况，以及对葡萄糖溶液的电化学响应等部分进行对比，综合分析材料、修饰方法等对制备的葡萄糖氧化酶电极的特性影响，评价电极特性。本研究成果可为测试电子供体与电子受体在同一微环境中的反应动力学提供有力的工具，将在化学、生物和环境领域的科研中得到应用，并具有良好的发展前景。更多还原

【Abstract】 Microsensor was firstly an important mean in the studies of biophysical andneural electrophysiological field, and was applied to environmental field since1990s.Since then, microelectrode became a powerful tool for characterization of thecharacteristic parameters’ concentration gradient in microenvironment between solid/liquid interface, which provides an important way of studying the microscopic masstransfer process and reaction dynamics theory of the liquid/solid interface.The rapid development of nanoscience and technology in recent years and itsapplication in micro-electrode field precipitating new types of nano microelectrode.At present, there is few research and analysis of microelectrode technique inenvironment-related issues, and there is great lack of independent research andcommercialization in micro-electrode topics.This study focus on widely used dissolved oxygen microelectrode and itsstructure. After optimize the guard-electrode, the new microelectrode was comparedwith traditional one from different aspects, such as residual current (I0), the linearcorrelation (R2), disturbance effects and resolution and so on. The results showsnewly designed dissolved oxygen microelectrode performance better than traditionalone: residual current reduced by about60%, with a tiny current of about300pA;linear correlation R2is above0.99; the presence of newly designed guard-electrodecan greatly stable the electrical signal, the disturbing effect of output can be reducedto about0.5%from3%to4%; with distinguished resolution below1nA.ZnO Nanorods were deposited on the surface of platinum electrode bylow temperature hydrothermal method, on which glucose oxidase wasimmobilized by electrostatic adsorption, thus nano-ZnO modified glucoseoxidase microelectrode was completed. The response time of thismicroelectrode was less than0.5s, with the lowest detection limit of2mmol/L, and the linear range is4mmol/L to30mmol/L. Linear correlationbetween glucose concentration and response peak current is0.9973. Anotherkind of nano-Au modified glucose oxidase microelectrode was fabricated indifferent mechanism. Gold nanoparticles were deposited by electrochemicaldeposition on the surface of carbon fiber, and glucose oxidase was submitjoint fixed onto. Gold nanoparticle modified glucose oxidase micro-electrode bared a response time less than1s,with the lowest detection limit of1mmol/L,and the linear range of1mmol/L to20mmol/L. The linear correlationbetween glucose concentration and response peak current is0.9471. Finally,two kinds of electrodes were compared and analyzed from the base material,the modified situation, and response to glucose solution and so on, toevaluated the effect of different material and modify choice on thecharacteristics of electrodes.Due to the enormous applications and prospects for development ofsensor technology in various fields, the study of different types ofmocro-electrode of far-reaching significance in the chemical and biologicaldevelopment and application, especially for environmental monitoring aspect,which can be used in the research of degradation kinetics from electron donorand electron acceptor in the same medium.更多还原