【作者】 鲍军方；

【导师】 瞿斌； 于锡娟；

【作者基本信息】 青岛科技大学 ， 应用化学， 2009， 硕士

【摘要】 纳米材料有“21世纪最有前途的材料”之美誉,被认为是跨世纪材料研究领域的热点。纳米颗粒具有比表面积大、表面反应活性高、吸附能力强、催化效率高等特性,为化学发光和传感器的发展提供了新的研究途径。本论文首先综述了纳米微粒的特性、制备方法及在传感器和化学发光中的应用。在此基础上,选择纳米金和纳米银为模型金属纳米粒子。一方面,研究纳米微粒在化学发光中的应用,探讨其参与液相化学发光的行为规律和机理等,为寻找新的化学发光体系奠定了基础;另一方面,研究纳米微粒在传感器中的应用,将适体技术和纳米科技相结合,利用纳米微粒作为探针在分子识别领域对物质进行检测。本论文的主要研究内容如下:1.发现纳米金能够增强铈(IV)-亚硫酸钠-诺氟沙星化学发光体系。通过对化学发光谱图、荧光光谱、紫外可见吸收光谱和透射电镜图进行研究,提出化学发光体系可能的发光机理为:纳米金能促进自由基的形成,并且加速纳米金表面的电子转移速度。测定的诺氟沙星线性范围为7.9×10-7 ~ 1.9×10-5 mol·L-1,检出限为8.2×10-8 mol·L-1。此方法被成功应用于尿液检测。2.基于铽(III)能敏化铈(IV)和亚硫酸钠化学发光体系检测诺氟沙星,注入纳米银后,体系的发光信号增强,据此建立了一种检测诺氟沙星的新方法。在最优条件下,测定了诺氟沙星线性范围为2.0×10-7 ~ 4.0×10-5 mol·L-1,检测限为3.0×10-8 mol·L-1。对化学发光可能的机理进行了探讨。3.利用Hg2+的核酸适体修饰纳米金形成探针,建立了一种定量检测Hg2+离子的方法。Hg2+适体吸附在纳米金表面,使纳米金的稳定性增强,抑制氯化钠对纳米金的团聚作用。溶液中有Hg2+离子存在时,由于适体与纳米金的吸附作用小于适体与Hg2+离子的亲和作用,纳米金失去适体保护在氯化钠作用下发生团聚。溶液颜色由红变蓝,紫外可见光谱最大吸收峰由520 nm红移至620 nm。在最优条件下,吸光度的比值(A620/A520)与Hg2+离子浓度在5.0×10-9 ~ 7.2×10-7 mol·L-1范围内呈线性关系,检测限可达3.3×10-10 mol·L-1。研究了K+、Ca2+等常见离子的干扰,结果表明,该方法具有良好的选择性。4.提出了一种采用纳米银为探针检测Hg2+离子的新方法。利用适体保护纳米银,抑制碘化钾对纳米银的团聚现象;若Hg2+离子存在,适体与Hg2+离子结合,纳米银失去保护发生团聚,通过紫外可见吸收峰的比值A584/A398对Hg2+离子进行检测。Hg2+离子线性浓度范围为4.00×10-9 ~ 2.09×10-6 mol·L-1,其检出限为5.84×10-10 mol·L-1。该方法对Hg2+离子有特异性,测定了实际水样中的Hg2+离子,为环境监测和生物样品分析提供了有力的工具。更多还原

【Abstract】 Nanoparticles, with their sizes in the range of l ~ 100 nm, are currently under intense investigation owing to their special properties. These materials exhibit size quantum effect, small size effect, surface effect, macroscopic quantum tunneling effect and dielectric confinement effect that differ from both their bulk material and the individual atoms from which they comprised. With these unique properties, nanoparticles are particularly attractive in the applications of chemiluminescence (CL) and sensor.In this dissertation, the physical and chemical properties of nanoparticles (NPs), the synthesis of nanoparticles and their applications in CL and sensor fields were reviewed. Furthermore, gold nanoparticles (gold NPs) and silver nanoparticles (AgNPs) are applied in liquid-phase CL system and the CL mechanism was thoroughly explored. Meanwhile, the sensors, constructed by the aptamer combining with nanoparticles, have been successfully used to detect mercury(II). The main research results are as follows:1. The CL system from the redox reaction of cerium(IV) and sodium sulfite enhanced by gold NPs is developed for the determination of norfloxacin (NFLX). CL profiles, UV-Visible spectra, fluorescence spectra, and transmission electron microscopy (TEM) studies are carried out before and after the CL reactions to investigate the CL enhancement mechanism. The mechanism is supposed to originate from the enhancer of gold NPs, which facilitates the radical generations and electron-transfer processes taking place on the surface of the gold NPs. Under the selected experimental conditions, a linear relationship was obtained between the CL intensity and the concentrations of NFLX in the range of 7.9×10-7 to 1.9×10-5 mol·L-1 and the detection limit was 8.2×10-8 mol·L-1. This method is successfully applied to the determination of NFLX in human urine. Chemiluminescence occurring on the surface of gold NPs presents a new view of the chemical reactivity and catalytic effect, which indicates that the proposed system is of great analytical potential. 2. Chemiluminescence was elicited in the system cerium(IV)-sulphite-NFLX sensitized by Tb3+ in acidic condition, which was remarkably enhanced in the presence of AgNPs in this work. Based on these observations, a new flow-injection CL method was developed for the NFLX determination. The CL intensity is directly proportional to the concentration of NFLX in the range of 2.0×10-7 to 4.0×10-5 mol·L-1 with a detection limit of 3.0×10-8 mol·L-1. The possible CL mechanism of the system was further explored.3. A method for Hg2+ quantitative determination was developed which the Hg2+ aptamer was used to modify gold NPs. The aptamer was absorbed onto the gold NPs which the gold NPs’stability against salt-induced aggregation was reinforced. But this attraction was weaker than the affinity between the target (Hg2+) and the aptamer. Addition of salt resulted in aggregation of gold NPs that led to red-to-blue color change if the proper Hg2+ and aptamer both were put into the gold NPs solution. The maximum absorption wavelength would change from 520 to 620 nm. Before detecting Hg2+, the concentrations of sodium chloride and aptamer were optimized, and the appropriate pH was chosen. Under optimal conditions, the absorption ratio A620/A520 was proportional to the concentration of Hg2+ in the range of 5.0×10-9 to 7.2×10-7 mol·L-1 and the detection limit was 3.3×10-10 mol·L-1. Interferences from selected inorganic ions were investigated and the proposed method was simple and sensitive.4. For highly selective and sensitive detection of Hg2+, a new approach was presented by use of aptamer and AgNPs (Apt-AgNPs) probe. Most of colorimetric methods previously reported employed gold NPs as sensing elements. In this work, AgNPs binding aptamer were used to detect Hg2+ against KI-induced aggregation. In the absence of Hg2+, the aptamer could protect AgNPs from KI-induced aggregation, whereas in the presence of Hg2+, aptamer combined with Hg2+ and AgNPs aggregated. Under optimum conditions, the Apt-AgNPs probe exhibited a high selectivity toward Hg2+ in the range of 4.00×10?9 ~ 2.09×10?6 mol·L-1, with a detection limit of 5.84×10?10 mol·L-1. The synthesis and remarkable properties of AgNPs help to extend the development of the Apt-AgNPs probe detecting metal ions. The proposed method was successfully applied for Hg2+ detection in three real samples with satisfactory results.更多还原