【作者】 杨琴；

【导师】 张友玉；

【作者基本信息】 湖南师范大学 ， 分析化学， 2007， 硕士

【摘要】 现场红外反射电化学光谱技术是一种重要的表面科学研究手段，它可以从原子和分子水平层次上揭示固／液界面的结构和电极反应动力学特征。现场红外衰减全反射光谱（FTIR-ATR）分析样品时不需化学制备，具有非破坏性的特点，在化学或生物过程监测和固／液界面吸附的研究中有独特的作用。电化学压电石英晶体微天平（EQCM）可动态监测电极表面低至纳克级的质量变化及溶液粘密度改变，能提供电极表面覆盖度及电化学过程的电容、电阻变化等信息。将这些方法联用可以得到生物或电化学过程的多维信息，从而为我们研究固／液界面过程提供更可靠的证据。本学位论文将电化学压电石英晶体微天平与现场红外反射光谱技术联用，将其应用于生物材料表面上蛋白质吸附、有机小分子的氧化还原、新型聚合物的合成及形成机理方面的研究。主要内容如下：1．综述了现场红外反射光谱技术与电化学石英晶体微天平的原理和近期研究进展。2．用电化学石英晶体阻抗法（EQCI）和衰减全反射红外光谱法（ATR）研究了纤维蛋白原（FIB）在纳米生物活性材料TiO₂和羟基磷灰石（HAP）上的吸附行为，获得了FIB吸附过程中电极表面的质量变化和电极／蛋白质界面双电层中电容变化以及FIB构象变化等信息。以两步骤连串反应机理分析FIB吸附动力学。结果表明，FIB在两种电极表面的吸附过程均分为吸附和重排两个过程，FIB在TiO₂上的吸附慢于在HAP上的吸附，且难达到稳态。根据Sauerbrey方程结合Martin方程估算了FIB在HAP和TiO₂上饱和吸附时的表面覆盖度，分别为1.67×10^-6g cm^-2和6.49×10^-6g cm^-2。红外谱图结果还表明，生物材料的表面组成对蛋白质吸附动力学和蛋白质结构变化均有影响。FIB在HAP表面吸附时的响应更大，并对蛋白质二级结构的变化影响更大。3．用EQCM和现场红外光谱电化学研究了碱性介质中L-色氨酸的电化学行为，考察了不同pH值和不同氧化电位对L-色氨酸电化学行为的影响，发现L-色氨酸在金电极上发生了不可逆的氧化还原反应，氧化还原过程有H⁺的参与。L-色氨酸氧化还原过程中电极上有物质（聚色氨酸）的沉积。扫描电子显微镜（SEM）图表明这种沉积物具有类似聚合物的形貌，用K₃Fe（CN）₆／K₄Fe（CN）₆探针对聚合物膜进行表征发现其阻碍了阴离子的电化学反应。研究了聚合物在0.1 M NaOH溶液中的电化学行为，发现聚色氨酸修饰膜的氧化还原反应也可能是不可逆的。4．用电化学-现场红外-压电石英晶体微天平三维联用技术研究酸性介质中邻甲苯胺和邻氨基酚的单聚和共聚并考察了共聚膜的电化学性质。电化学压电结果表明，共聚物的电化学性质不同于两种单聚物，两种单体的相对浓度对共聚膜的生成速率有较大影响，共聚物的稳定性和电活性比单聚物较好。现场压电红外光谱电化学结果表明，单聚和共聚是不同的过程，共聚不是聚邻甲苯胺和聚邻氨基酚的简单混合，而是两种单体通过-NH-基团头尾相连形成的一种新的聚合物。更多还原

【Abstract】 In situ Fourier transformation infrared （FTIR） reflectionspectroelectrochemistry is a useful and powerful tool to study the ology of thesurface. It can provide the information about the interface of solid/liquid andabout the reaction kinetics on the electrodes. In situ Fourier transforminfrared-attenuated total reflectance （FTIR-ATR） measurement is nondestructiveto the samples and the samples need no chemical pretreatment. FTIR-ATR hasbeen applied to in situ study the chemical and biochemical process and theadsorption occurring on the liquid/solid interface. The electrochemical quartzcrystal microbalance （EQCM） can be used to synchronously determine multiplechemical/physical parameters and study materials characteristics during anelectrochemical perturbation, such as electrode-mass changes down to thenanogram level, the elasticity of modified films and the solution viscosity anddensity.Combination techniques of piezoelectric sensor and spectrumelectrochemistry can provide multidimentional information during the chemicaland biochemical process and help us to understand the reaction on theliquid/solid interace more adequately and reliably. In this thesis, we studied thecombination of EQCM and in situ FTIR techniques, and applied thecombination techniques to study the adsorption of protein on biomaterial, theredox of small organic molecule and the electrosynthesis of new polymer.The main content of this dissertation are summarized as follows: 1. The recent researches using in situ FTIR techniques and EQCM are brieflyreviewed.2. The electrochemical piezoelectric quartz crystal impedance （EQCI）, acombined technique of piezoelectric quartz crystal impedance （PQCI） andelectrochemical impedance （EI）, and FTIR-ATR spectroscopy were utilizedto study in situ adsorption of fibrinogen onto biomaterial surfaces of TiO₂ andhydroxyapatite (Ca₁₀（PO₄）₆（OH）₂). The adsorption kinetics and mechanism offibrinogen adsorption onto these biomaterial surfaces were investigated. TheEQCI and FTIR-ATR measurement results suggested that two consecutivesteps occurred during the adsorption of fibrinogen onto TiO₂ andhydroxyapatite （HAP） films. The fibrinogen molecules were firstly adsorbedonto the films. And then rearrangement of adsorbed fibrinogen ormulti-layered adsorption occurred. The FTIR-ATR spectroscopy studies alsoshowed that the structure of the biomaterials has affected the adsorptionkinetics and the secondary structure of the adsorbed fibrinogen molecules.More fibrinogen molecules were adsorbed onto HAP surface and the secondstructure of the fibrinogen molecules adsorbed onto HAP surface changedmore notably.3. In situ FTIR spectroelectrochemistry and EQCM were used to study theelectrochemical hehaviors of L-Tryptophan （Trp） on polycrystalline Auelectrode and PQC Au electrode in alkaline media. The electrochemicalredox process of L-Tryptophan was studied under different oxidationpotentials in NaOH solution and in electrolyte solutions with different pHvalue by applying cycle voltammetry scan. The resultes showed that theelectro-oxidation of L-Tryptophan was irreversible involving transfer ofprotons. There was polymer （poly（Trp）） deposited on the Au electrode surface which induced by the redoxtion of L-Tryptophan. The EQCM andin stiu FTIR spectra results show that the redox process of poly（Trp） may wasalso irreversible. And the electrochemical reaction of anionic species wereblocked by the poly（Trp） film when the poly（Trp） modified electrode CVin the K₃Fe（CN）₆/K₄Fe（CN）₆ solution.4. The homopolymerization and copolymerization of o-toluidine （OT） ando-aminophenol （OAP） were studied in H₂SO₄ solution with in situpiezoelectric FTIR spectroelectrochemisty methods. The films were obtainedby applying cycle voltammetry scan at the rate 50 mV s^-1 between -0.1 to 0.9V vs. Ag/AgCl electrode in 0.5 M H₂SO₄ solution. The results showed thatthe electrochemical properties of the copolymer （poly（OT-co-OAP）） wasdifferent from that of the two polymers obtained from single monomer （POTor POAP）. The copolymerization speeds were notablely affected by the feedratio of the monomers. Poly（OT-co-OAP） obtained under proper conditionswas electrochemically active at a broad pH range. Poly（OT-co-OAP） is morestable than POT and POAP as well. POT, POAP and poly（OT-co-OAP） werestudied with in situ piezoelectric FTIR spectroelectrochemistry methods. TheFTIR spectroscopic results and frequency shiftes indicate that the anion ionscan dope into the three polymers accompanying theprotonation/deprotonation reaction process. The copolymer formed throughhead-to-tail coupling of the two monomers via -NH- groups was a newpolymer rather than a mixture of homopolymers.更多还原