动态表面增强拉曼光谱最佳热点的调控及性能研究

发布时间：2018-05-24 12:23

本文选题：动态表面增强拉曼光谱 + 最佳热点　；参考：《中国科学技术大学》2017年硕士论文

【摘要】：表面增强拉曼光谱(SERS)自20世纪70年代发现以来,由于能够提供分子的指纹信息、非破坏性、以及超灵敏性特点,SERS技术已经成为一个强有力的分析工具,可应用于化学、生物以及环境分析。近些年来,本课题组发展的动态表面增强拉曼光谱(D-SERS)凭借其高灵敏性,重现性和稳定性以及实时检测的特点也逐渐受到关注。众所周知,纳米材料的形貌对SERS增强效果有很大的影响,各项异性的纳米粒子(纳米星、三角形、管状等)作为增强基底灵敏性很高,但重现性很低。在SERS检测中,获得重现性好、可靠性高的检测结果,合成单分散的纳米粒子是至关重要的。本论文主要是基于单分散的纳米粒子作为SERS基底,结合D-SERS方法的诸多优点来开展的一系列工作。第一章简单的介绍了 SERS的基本概念、原理和基底材料,SERS在医学、单分子检测、公共安全方面的应用。重点介绍了 D-SERS的发现、发展过程以及D-SERS的特征和优点,目前存在的问题和研究思路。第二章是基于D-SERS能够实现实时检测的特点,再结合双组份分析法来实时研究两种同分异构体2,2'-Bpy和4,4'-Bpy的竞争吸附。通过D-SERS的实时监测研究发现2,2'-Bpy和4,4'-Bpy的吸附是一个动态竞争的过程。此动态吸附的变化过程在普通的干态方法下是无法检测到的,D-SERS实时检测的特点为研究分子的竞争吸附提供了方法。第三章提出了 "最佳热点"的概念,并基于最佳热点建立了可靠的定量分析方法。采用原位小角X射线散射技术(SAXS)实时地追踪"最佳热点"的形成过程,结果表明在单分散纳米溶胶蒸发的过程中确实形成了 "最佳热点"。采用4-巯基吡啶(4-mpy)作为内标分子,结晶紫(CV)作为模型分子进行方法验证,将D-SERS最佳热点处的最强信号强度用于统计分析。结果表明,CV的相对强度与浓度的负对数成线性关系,即可以实现定量检测。最终,通过这种方法,两种毒品摇头丸(MDMA)、a-甲基色胺二盐酸盐(a-MT)以及三聚氰胺都可以实现定量检测。第四章是在第三章的基础上进一步进行的探索。运用D-SERS过程中的"最佳热点"结合免内标(internal standards-free)的方法实现对一类特殊分子的定量检测。这类特殊的分子是指具有较大散射截面和对称性结构的分子,例如三苯甲烷染料。CV是廉价的三苯甲烷染料,它能帮助鱼类有效对抗真菌和寄生虫感染。但由于这些染料对人类有致突变和致畸作用,在水产养殖中是禁止使用的。因此,准确测定三苯甲烷染料的浓度是至关重要的。结果表明,采用这种方法可以实现对三苯甲烷染料的定量检测。第五章主要是在第三和第四章内容的基础上来探索"最佳热点"的可控性。最佳热点处具有很多的优点,然而最佳热点的存在时间非常短,变化非常快,而且这一过程是不可逆的。因此,我们希望采用不同的方法将最佳热点的存在时间延长,并通过小角X射线散射(SAXS)实时追踪方法的可行性。结果表明通过封闭和液封都可以实现对热点的控制,这对D-SERS乃至SERS而言都有着极其重要的意义。
[Abstract]:Since the surface enhanced Raman spectroscopy (SERS) was discovered in 1970s, because of its ability to provide molecular fingerprint information, nondestructive, and super sensitive characteristics, SERS technology has become a powerful analytical tool that can be applied to chemical, biological and environmental analysis. In recent years, the dynamic surface enhanced Raman light (SERS) developed by our group has been developed. D-SERS, with its high sensitivity, reproducibility and stability as well as the characteristics of real-time detection, has been paid more attention. It is known that the morphology of nanomaterials has a great influence on the enhancement of SERS. The sensitivity of various nanoparticles (nanoscale, triangle, tube, etc.) is very high, but the reproducibility is very low. The detection of SERS is very low. In order to obtain good reproducibility and high reliability detection results, the synthesis of monodisperse nanoparticles is very important. This paper is based on a series of work based on the advantages of the single dispersed nanoparticles as the SERS substrate and the D-SERS method. The first chapter briefly introduces the basic concepts, principles and substrate materials, SER of the SERS. The application of S in medicine, single molecule detection and public safety. This paper focuses on the discovery of D-SERS, the development process, the characteristics and advantages of D-SERS, the existing problems and research ideas. The second chapter is based on the characteristics of the real-time detection based on the D-SERS, and then combines the dual component analysis method to study the two isomers in real time, 2,2'-Bpy and the real time. The competitive adsorption of 4,4'-Bpy. Through real-time monitoring of D-SERS, it is found that the adsorption of 2,2'-Bpy and 4,4'-Bpy is a dynamic competition process. The dynamic adsorption process can not be detected under the ordinary dry state method. The characteristic of real-time detection of D-SERS provides a method for studying the competitive adsorption of molecules. The third chapter puts forward the "most" The concept of "good hot spot" and a reliable quantitative analysis method based on the best hot spot were established. In situ small angle X ray scattering (SAXS) was used to track the formation process of "the best hot spot" in real time. The results showed that the best hot spot was formed in the process of evaporation of monodisperse nanossols. 4- mercapto pyridine (4-Mpy) was used as the internal standard. Crystal violet (CV) is used as a model molecule to verify the strongest signal intensity at the best hot spot of D-SERS. The results show that the relative intensity of CV is linear with the negative logarithm of the concentration, that is, the quantitative detection can be achieved. Finally, two kinds of drug ecstasy (MDMA) and a- methyl chromamine two hydrochloride (a-MT) are obtained by this method. And melamine can be quantified. The fourth chapter is a further exploration on the basis of the third chapter. Using the "best hot spot" in the D-SERS process and the method of internal standards-free, the quantitative detection of a class of special molecules is realized. This special molecule refers to the large scattering cross section and symmetry. Structural molecules, such as the triphenyl methane dye.CV, are cheap triphenyl methane dyes that help fish effectively against fungal and parasitic infections. But because these dyes have mutagenic and teratogenic effects on human beings, it is forbidden to use in aquaculture. Therefore, it is essential to determine the concentration of three benzyl dyes accurately. The fifth chapter is mainly based on the content of the third and fourth chapters to explore the controllability of "the best hot spot". The best hot spot has many advantages, however, the best hot spot has a very short time, very fast change, and this process is irreversible. Therefore, we hope to use different methods to extend the time of the best hot spot, and through the feasibility of the small angle X ray scattering (SAXS) real-time tracking method. The result shows that both the sealing and the liquid seal can realize the control of the hot spot, which is of great significance for the D-SERS and even the SERS.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O657.37

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