【作者】 范亚；

【导师】 黄承志； 龙云飞；

【作者基本信息】 西南大学 ， 分析化学， 2010， 硕士

【摘要】 金纳米粒子和CdS量子点作为经典的纳米材料,因其尺寸小,具有各自独特的电子、催化及光学特性而在生物医学成像、DNA杂交和无机金属离子检测等方面得到广泛的应用。本文利用硫离子修饰后的金纳米粒子跟溶液当中的汞离子发生反应,并基于溶液颜色变化建立了一种运用共振光散射技术可视化检测汞离子的方法；此外,我们还分别研究了硫离子修饰后的金纳米棒,富硫离子的CdS量子点跟汞离子以及富镉离子的CdS量子点跟半胱氨酸的作用。主要研究内容为：(1)合成几种大小不同的金纳米粒子,用硫离子对其进行修饰,修饰后的金纳米粒子用激光拉曼光谱进行表征。将修饰后的金纳米粒子用于溶液中汞离子的检测,结果发现金纳米粒子发生聚集,溶液颜色呈现红-紫-蓝的变化,且光散射信号在汞离子浓度为0.025-0.25μmol·L-1的范围内呈线性增强,检出限(3σ)为0.013μmol·L-1,这个方法成功用于环境样中汞离子的测定,该方法经济,简单,快速,灵敏度高,有一定应用价值。(2)合成颜色呈粉红色的金纳米棒,用硫离子对其修饰,在弱酸性介质中,硫的一端与金纳米棒共价作用结合后,另一端与汞离子结合形成纳米复合物,使体系的共振光散射强度增强。光散射强度在汞离子浓度为0.1-10μmol·L-1范围呈线性增加,检出限为0.096μmol·L-1。(3)用柠檬酸三钠和六偏磷酸钠做稳定剂,控制反应初期S2-的物质的量大于Cd2+物质的量,在冰水浴中一步合成了富硫离子的CdS量子点。以富硫离子的量子点为荧光探针,选择性地检测溶液当中的汞离子。考察了不同缓冲体系、缓冲pH值、量子点浓度等多种因素的影响,在最佳实验条件下,测定汞离子的线性区间为0.05.33μmol·L-1,检出限为O.08μmol·L-1,由此我们建立了一种基于表面富硫离子的CdS量子点检测汞离子的方法。(4)以柠檬酸钠和六偏磷酸钠为稳定剂,控制反应初期S2-的物质的量小于Cd2+物质的量,在冰水浴中一步合成富Cd2+的CdS量子点。以富Cd2+的CdS量子点为荧光探针,选择性地检测半胱氨酸。实验研究发现半胱氨酸对量子点的荧光有增敏效应,在pH2.87的B-R缓冲溶液,体系的荧光强度增加值与半胱氨酸的加入量成正比。该方法的检出限是0.01μmol·L-1,选择性好,回收率结果满意。更多还原

【Abstract】 Owing to the small size, electronics, catalytic and optical properties, gold nanoparticles and CdS quantum dots acted as the classic nanometer materials have been wildly used in the fields of biomedical imaging, DNA and inorganic metal ion detection since their discovery. In the thesis, we used S2" modified gold nanoparticles to detect the Hg2+in the solution by the resonance scattering technology, and a visual method for Hg2+was further developed based on the color change of this solution. In addition, new analytical methods for Hg2+determination were proposed respectively based on the S2-modified gold nanorods and sulfide-capped CdS quantum dots. Moreover, we studied the interaction between the cadmium-capped CdS quantum dots with the cysteine. The main contents are listed as follows:(1) We had synthesized several sizes of gold nanoparticles and modified them with S2-. After modification, the gold nanoparticles were characterized by Laser Raman Spectra and used for the detection of Hg2+in the aqueous solution. Our results showed the gold nanoparticles aggregated together and the color of the solution changed from red to violet until blue. The enhanced RLS intensities were found to be proportional to the concentration of Hg2+in the range of 0.025-0.25μmol·L-1 with a detection limit (3σ) of 0.013μmol·L-1. This method was successfully used for the detection of environmental samples and there were many merits of this way, such as simple and small measuring structure, high sensitive, fast determination, broaden adaption environment and so on, so having certain application value.(2) We had synthesized pink gold nanorods and modified them with S2-. In the acidic medium, one side of sulfur reacted with the gold nanorods by the covalent binding effect and the other side combined with mercury to form Hg-S bond, so the distance of gold nanorods decreased and the resonance light scattering (RLS) intensities of the system increased greatly. Experiments showed that the enhanced RLS intensities (ΔIRLS) were proportional to the concentration of Hg2+in the range of 0.1-10μmol·L-1. The correlation coefficient of linear equations was 0.9910 with a detection limit of 0.096μmol·L-1.(3) Using sodium hexametaphosphate and sodium citric as stabilizing substances, the sulfide-capped CdS quantum dots had been fabricated in the icewater bath by controlling the initial amount of S2-more than the initial amount of Cd2+. The sufide-capped CdS quantum dots were used as fluorescence probes for the selective determination of trace amounts of Hg2+based on the evident quenching action of Hg2+ on the fluorescences of quantum dots. The effects of buffer type, pH value and CdS quantum dots concentrations were investigated. Under optimum condition, the value of ((Fo-F)/F) upon the addition of Hg2+were found to be proportional to the concentration of Hg2+in the range of 0.05-33μmol·L-1 with a detection limit of 0.08μmol·L-1. Thus, a new fluorometric method for Hg2+based on the sulfide-capped CdS was developed.(4) Controlling the initial amount of Cd2+more than the initial amount of S2-, the cadmium-capped CdS quantum dots were prepared by means of sodium hexametaphosphate and sodium citric as stabilizing substances in the icewater bath. The cadmium-capped CdS quantum dots were used as fluorescence probes for the selective determination of cysteine. Our results showed that the cysteine could increase the fluorescence intensities of the CdS quantum dots. In the B-R buffer solution with pH value of 2.87, the value of ((Fo-F)/Fo) upon the addition of Hg2+were found to be proportional to the concentration of cysteine with a detection limit of 0.01μmol·L-1. Our results showed that there was a best selectivity and satisfactory recovery.更多还原