【作者】 张友玉；

【导师】 姚守拙； 谢青季；

【作者基本信息】 湖南大学 ， 分析化学， 2005， 博士

【摘要】 压电石英晶体传感器可传感检测许多化学/生物反应或过程中所伴随的纳克级电极质量变化和修饰膜的粘弹性、溶液密度、粘度、电导率、介电常数等参数的改变。红外光谱电化学技术可在分子水平上现场表征电化学过程。获得电化学过程中电氧化还原物种的结构变化信息。 传统的压电石英晶体振荡器法与电化学联用技术只能在电化学研究过程中同步获得振荡频率的响应信息。利用压电石英晶体阻抗技术能获得多维压电信息的特点,研究压电石英晶体阻抗与电化学阻抗以及红外光谱电化学方法的联用技术将可进一步拓宽研究视野,并可获得研究体系更加丰富的信息。本学位论文建立了压电石英晶体阻抗与电化学阻抗联用技术以及压电石英晶体阻抗-红外反射光谱-电化学三维联用新技术,结合荧光光谱、扫描电子显微镜等分析手段,在蛋白质在固体表面的吸附以及蛋白质与小分子的作用、溶胶的形成和聚沉过程、吡哆醇的电化学氧化以及聚邻氨基苯酚的电沉积和电化学性质等方面开展了如下一些创新研究工作,获得了一些新的研究结果: 1) 建立了压电石英晶体阻抗分析和电化学阻抗联用技术,将其用于几种蛋白质在裸金及聚苯胺、几种硫醇分子修饰电极上的吸附以及蛋白质与单宁酸的作用的研究,现场同步获得了蛋白质吸附以及与小分子作用过程中的压电石英晶体谐振频率、动态电阻、动态电感、动态电容、静态电容、电声阻抗谱的半峰宽、双电层电容等多参数的变化信息。主要如下:(1)研究了溶菌酶在金电极和几种硫醇分子修饰金电极上的动态吸附过程及其动力学,发现其吸附量与电极表面的亲水性和电极电位密切相关,其中在强疏水性的正十二硫醇修饰电极上吸附量最大,负电位有利于溶菌酶在电极表面的吸附;(2)提出了以离子掺杂法调变聚苯胺修饰电极表面亲水性的电极修饰方法,制备了不同性质的聚苯胺修饰电极。实验发现在含临界胶束浓度的十二烷基磺酸钠(SDS)的聚合液中制得的电极修饰膜疏水性最强,牛血清白蛋白(BSA)和纤维蛋白原在其表面的吸附量最大;(3)结合荧光光谱研究了牛血清白蛋白与单宁的相互作用。结果表明低浓度单宁与BSA的结合摩尔比为2:1,高浓度单宁则诱导BSA沉淀。 2) 首次采用压电石英晶体阻抗技术现场监测了液体溶胶的生成和聚沉过程,将更多还原

【Abstract】 Piezoelectric quartz crystal （PQC） sensor can sensitively detect the changes in electrode mass loading and film viscoelasticity as well as solution viscosity, density, conductivity, and dielectric constant in chemical/biological reactions and processes. Infrared spectroelectrochemistry can characterize an electrochemical process at the molecular level by acquiring real time information about molecular structure of related species.The conventional combination of piezoelectric quartz crystal oscillator with electrochemistry technique generally only provides piezoelectric information of oscillation frequency in electrochemical processes. Piezoelectric quartz crystal impedance （PQCI） technique is capable of providing multidimensional piezoelectric information of the investigated system. It is expected that the novel combination of PQCI with electrochemical and/or infrared spectroelectrochemical technique（s） can acquire much more abundant information about the investigated system.In this dissertation, two combination techniques have been established, namely, PQCI in combination with electrochemistry and further with infrared spectroscopy, which have been used to study protein adsorption onto solid surfaces, the interaction between protein and tannine, generation and deposition of nano colloid, electrochemical oxidation of pyridoxol （PN）, and electrodeposition and electrochemical properties of poly（o-aminophenol）, with the help of fluorescence spectroscopy and scanning electric microscopy （SEM）. The main work is summarized as follows:1) We established the combination technique of PQCI with electrochemical impedance. The adsorption of proteins on bare gold, and polyaniline or thiols-modified Au electrodes, and the interaction between proteins and small molecules were investigated in situ by using quartz crystal impedance analysis in combination with electrochemical impedance technique. Multidimensional parameters, such as resonance frequency, motional resistance, motional inductance, motional capacitance, the value of half peak width of theelectroacoustic conductance spectrum (δf_G1/2 as well as the electrical double-layer capacitance were obtained. The main results are as follows: （1） The dynamics of the adsorption process of lysozyme onto bare and thiols-modified Au electrodes were monitored and studied. It is found that the adsorbed amount of lysozyme is strongly dependent on the surface hydrophilicity and electrode potential. The maximal adsorption amount was observed on the n-dodecanethiol-modified Au electrode, while the adsorption was favorable at negative electrode potentials. （2） A new electrode-modification method capable of modulating the electrode-surface hydrophilicity via ion-doping protocol was put forward. A series of modified electrodes with different hydrophilicity was thus obtained. The maximal adsorption amounts of bovine serum albumin （BSA） and fibrinogen were obtained on the polyaniline film deposited in an aniline solution containing sodium dodecyl sulfate （SDS） at its critical micelle concentration （CMC）. （3） The interaction between tannin and BSA was studied by using the combining technique of PQCI and electrochemical impedance spectrum （EIS） and fluorescence spectrophotometry. In diluted tannin solutions, the molar ratio of tannin binding to BSA was 2:1. While in concentrated tannin solutions, induced precipitation of BSA was observed.2) Piezoelectric quartz crystal impedance technique was introduced into the sol-gel research field to monitor in situ the processes of generation and precipitation of colloids. The main results are as follows: （1） Generation and precipitation of the ferric hydroxide sol in Fe（NC>3）3 aqueous solutions at 90°C were monitored in situ. Three basic steps, sol generation and simultaneous adsorption, adsorption equilibrium, and precipitation of ferric hydroxide sol, were identified and discussed respectively. The critical concentration of Na2SO.? for sol coagulation was measured. （2） Through hydrolysis of tetraethyl orthosilicate in alcohol solution containing 6-15 mol L"1 of water and 0.2 - 2.0 mol L"1 of ammonia, generation and precipitation process of sub-micro-sized monodispersed silica particles were monitored. It is found that the effect of ammonia concentration on the hydrolytic reaction was larger than that of water, and that the reaction can be analyzed by quasi first-order reaction kinetics. The particle’s distribution density and its mass coverage were calculated from the data obtained by scanning electron microscope （SEM）and piezoelectric impedance.3) A new combined technique, i.e. in situ quartz crystal impedance in combination with infrared spectroscopy and electrochemistry, was established in this work. The electrochemical oxidation process of pyridoxol （PN） was investigated with the combined technique of piezoelectric quartz crystal impedance and electrochemistry and the technique of infrared spectroelectrochemistry. The electrodeposition and the electrochemical redox process of poly-o-aminophenol in acidic solutions were investigated with the technique of in situ quartz crystal impedance combining with infrared spectroscopy and electrochemistry, and it was used as an exemplum for the application of the novel combined technique. The main results are as follows: （1） The major tautomeric equilibriums of PN molecules at various pH were studied. A lactone form of PN as an intermediate of PN oxidation and adsorption on gold surface was detected. The oxidation mechanism of PN in alkaline solution was proposed. （2） Piezoelectric infrared spectroelectrochemistry was successfully used to investigate the electrochemical deposition and electrochemical properties of poly-o-aminophenol. The mass changes of polymeric film, ion-doping behaviors, and information about the chemical structural changes of the film structure were obtained and discussed. The results indicated that this new method could be widely applied to the investigations on electrode-surface-relevant processes.更多还原