纳米二氧化钛修饰的石英晶体微天平化学传感器

【作者】 戴鸿娟；

【导师】 司士辉；

【作者基本信息】 中南大学 ， 分析化学， 2008， 硕士

【摘要】 因为传感器具有仪器设备简单、实时响应、易于操作和费用低廉等特点,对传感器的研究得到了分析化学界的普遍关注。常规压电传感器的应用研究始于上个世纪八十年代初,并已广泛应用于临床免疫学、血液流变学、生物化学及分子生物学,材料物理化学等众多领域。本研究利用石英晶体微天平的质量响应探讨了纳米二氧化钛膜对铅离子的吸附性能,建立了一种铅离子化学传感器;基于顺、反丁烯二酸空间结构上的差异研究了它们在纳米二氧化钛膜上的吸附差异性及紫外光照下其降解速率的差别;最后探讨了超声振荡下液体的密度和粘度发生改变时石英晶体微天平的频率变化情况,研究结果表明:（1）该电极对铅的最佳吸附条件为pH=7,TiO₂涂层厚度为0.4μm,温度为20℃,吸附时间为10 min,在2.04×10^-6～5.20×10^-8mol·L^-1浓度范围内,频率变化值与Pb（Ⅱ）的浓度呈很好的线性关系,其线性方程为△f=1.43-6.47C（r=0.9986）,检测限为6.85×10^-8mol·L^-1,且该纳米二氧化钛膜的再生性能良好,用于实际样品测定,结果令人满意;（2）顺、反丁烯二酸主要是通过其分子内的羧基与TiO₂表面上的羟基发生静电作用而吸附在TiO₂表面,红外谱图数据显示:丁烯二酸与TiO₂的吸附是通过其分子内的羧基形成二齿桥状物来完成的,其吸附平衡常数分别为4×10³ L·mol^-1和2.9×10³L·mol^-1;随着pH值的升高,纳米TiO₂对顺、反丁烯二酸的吸附作用逐渐减弱,当pH＜pzc（TiO₂）时,丁烯二酸的降解速率随pH值的升高而降低,当pH＞pzc（TiO₂）时,丁烯二酸的降解速率却随pH值的升高而升高,且顺丁烯二酸的降解速率要大于反丁烯二酸。（3）超声波对石英晶体微天平的振荡频率会产生一定的影响,且超声振荡下石英晶体微天平的频率随着溶液密度和粘度的增大而减小。更多还原

【Abstract】 Because of real-time monitoring,simple equipment,easy operation,and low cost,sensor has gained considerable interest in analytical science.The research of normal piezoelectric quartz crystal （PQC）was carried out in earlier 1980’s and had been widely applied in the fields of clinic immunology,hemorheology,biochemistry, molecular biology and material physical chemistry.The quality response of quartz crystal microbalance was used to investigate the adsorption behavior of nano-sized TiO₂ particles coating to Pb（Ⅱ）,a lead ion chemistry sensor was established.The difference of adsorption and degeneration speed under ultraviolet illumination on nano-sized TiO₂ particles coating were discussed based on the butenedioic acids’ spatial structure difference.The frequency shift of quartz crystal microbalance was also discussed at last under the supersonic vibration when the density and viscosity of the solution were changed.The results indicated that:（1）The best adsorption conditions of nano-sized TiO₂ to Pb（Ⅱ） were:pH=7,the thickness of TiO₂ coating was 0.4μm,the temperature was 20℃,the adsorption time was 10 minutes.A good linear relationship between the value of frequency shift and the concentration of Pb（Ⅱ）was obtained in the range of 2.04×10^-6～5.20×10^-8mol·L^-1 with the linear equation△f=1.43-6.47C（r=0.9986）,and the detection limit 6.85×10^-8mol·L^-1.The reproductive properties of the nano-sized TiO₂ particles coating were good and satisfactory when applied to the determination of trace lead in environmental water sample.（2）The butenedioic acids were adsorbed on the TiO₂ surface mainly by the static electricity function between their intramolecular carboxyl groups and the TiO₂ surface hydroxyl groups.The infrared spectrogram data indicated that surface coordination may occur through bridging bidentate carboxylates groups.Their adsorption equilibrium constants were 4×10³ L·mol^-1and 2.9×10³ L·mol^-1 respectively.The adsorption of nano-sized TiO₂ to butenedioic acids gradually weakened with the increase of pH.The degeneration rates of butenedioic acids were decreased with the increased pH when pH＜pzc（TiO₂）and rised with the increased pH when pH＞pzc（TiO₂）.Also the maleic acid degeneration rate was bigger than the fumaric acid.（3）The ultrasonic wave had certain influence on the oscilation frequency of quartz crystal microbalance.The frequency of quartz crystal microbalance decreased with the density and the increased viscosity of the solution under the supersonic vibration.更多还原