基于金属-有机骨架复合材料的eTLC-SERS方法研究

发布时间：2018-04-17 00:03

本文选题：薄层色谱 + 增强薄层色谱板　；参考：《第二军医大学》2017年硕士论文

【摘要】：表面增强拉曼光谱(Surface-enhanced Raman Spectroscopy,SERS)法是一种特征性强、灵敏度高的分析方法,其可提供大量物质的特征光谱信息。然而,在实际应用时,目标待测物多处在复杂体系中,SERS技术获取繁杂光谱信息后无法进一步提取目标化合物的SERS光谱信息。此外,在部分复杂体系中,一些SERS响应弱的组分的信号往往被SERS响应强的组分所掩盖。因此,在SERS检测前,对复杂体系中待测组分进行简单分离是十分有必要的。常用的分离方法有高效液相色谱法(HPLC)、气相色谱法(GC)、毛细管电色谱法(CE)、薄层色谱法(TLC)等。其中,TLC-SERS联用法因具有简单、快速及无需昂贵设备等优点而备受关注。TLC-SERS法分析步骤如下:将混合样品在TLC板上分离后,对分离后斑点进行定位,然后在定位斑点表面滴加SERS活性基底(金属溶胶),再将定位斑点置于拉曼光谱仪下进行检测。但是这种方法存在一些缺点:1.金属溶胶会对色谱分离后斑点重叠化合物的SERS检测产生干扰;2.一些化合物在紫外灯(UV254/365)和可见光下均不可见,分离后斑点无法定位,也就无法进行SERS检测;3.斑点会发生横向扩散以及二次扩散,导致检测灵敏度较低。为了改善常规TLC-SERS技术的不足,本研究建立了两种新型TLC-SERS方法。一种是:采用金属纳米粒子修饰的MIL-101骨架材料(AuNPs/MIL-101)对常规TLC板进行功能化,使其成为一种可分离的SERS基底,本文称这种新型TLC板为增强薄层色谱(enhanced Thin Layer Chromatography,简称eTLC)板。将eTLC板与SERS技术结合,待测样品在eTLC板上分离后,沿着展开方向采用激光逐点扫描的方式进行检测,板上所有化合物的信息都将被收集,包括斑点重叠和斑点不可见化合物。另一种是:采用色谱层析硅胶GF254制备宽度为2 mm的窄带TLC板,待样品在窄带TLC板上分离后,在分离斑点表面喷洒银溶胶,然后进行SERS检测。结果表明,窄带TLC-SERS法具有简便、快速、灵敏的优点,可改善常规TLC-SERS法斑点横向扩散和二次扩散的不足,而且降低了固定相用量,节约了成本。本研究分为两个部分:1)第一部分,根据文献中方法制备AuNPs/MIL-101复合材料,然后将复合材料和色谱硅胶按一定比例混合制备eTLC板;采用罗丹明6G作为探针分子,对混合比例、润湿剂种类及浓度、拉曼检测参数、eTLC板信号的重现性及稳定性等进行摸索和确定,成功建立了eTLC-SERS分析技术,并采用建立的eTLC-SERS分析技术对TLC分离后斑点重叠和斑点不可见的化合物进行检测。2)第二部分,制备了窄带TLC板,然后将其和SERS技术结合,建立了窄带TLC-SERS分析方法,并考察了固定相用量、灵敏度、检测限等因素。本研究的结果如下:1)制备出SERS增强性能最佳、均一性及稳定性好的eTLC板;2)建立eTLC-SERS法,确定最佳SERS检测条件,其中润湿剂种类为盐酸,浓度为0.01 mol/L,体积为5μL,拉曼激光功率为90 mW,积分时间为5 s;3)利用eTLC-SERS法检测TLC分离后斑点重叠和斑点不可见的化合物,成功鉴别出重叠斑点的组分及准确找出了不可见斑点的确切位置,实现了斑点重叠化合物和斑点不可见化合物的简单、快速以及灵敏的检测;4)制备出窄带TLC板,建立了窄带TLC-SERS法。与常规TLC-SERS法相比,该方法的灵敏度更高、检测限更低,且固定相用量仅为常规TLC板的8%。本研究首次成功建立了eTLC-SERS分析方法,并将其用于斑点重叠和斑点不可见化合物的检测。研究表明,该法没有外加金属溶胶基底的干扰,具有简单、灵敏度高、稳定性强等优点。其次,本研究建立了窄带TLC-SERS分析方法,其与常规TLC-SERS法相比,灵敏度更高,且固定相用量少,节约了成本。综上所述,本文建立的两种新型TLC-SERS分析方法均在一定程度上改善了常规TLC-SERS方法的不足,为TLC-SERS联用技术注入了新的活力。
[Abstract]:Surface enhanced Raman spectroscopy (Surface-enhanced Raman Spectroscopy, SERS) is a strong feature, high sensitivity analysis method, which can provide a large number of characteristic spectral information of material. However, in practical application, the target analytes in complex systems, SERS technology gets complicated spectral information after no further extraction of SERS the spectral information of the target compounds. In addition, in the part of the complex system, some SERS response weak signal components tend to be strong SERS response components cover. Therefore, before SERS detection, it is very necessary for simple separation of analytes in complex systems. There are commonly used high performance liquid separation method chromatography (HPLC), gas chromatography (GC), capillary electrochromatography (CE), thin layer chromatography (TLC). The TLC-SERS method with simple, fast and without expensive equipment has attracted attention.TLC-SER S analysis steps are as follows: the sample on the TLC board separation after mixing, the localization of separated spots, and then add the SERS active substrate in the positioning surface spots (metal sol), and then drops will be placed under the spot detection and localization of Raman spectrometer. But this method has some disadvantages: SERS detection of 1. metal sol after chromatography spots overlap compounds interference; 2. compounds (UV254/365) in the UV light and visible light are not visible, separated spots can't locate cannot be detected by SERS; 3. spots occur lateral diffusion and two diffusion, leading to low detection sensitivity. In order to improve the shortcomings of conventional TLC-SERS Technology, this study established two new TLC-SERS methods. One is: MIL-101 matrix material using metal nanoparticles modified (AuNPs/MIL-101) function of the conventional TLC plate, make it become a branch SERS from the base, the new board is called TLC (enhanced Thin Layer enhanced TLC plate Chromatography, referred to as eTLC). Combining the eTLC board and the SERS technology, the sample was separated on a eTLC board, measured along the direction by laser point scanning mode, all information compound board will be collected, including spot overlap and spots invisible compounds. The other is: using silica gel GF254 chromatography preparation for narrowband TLC 2 mm in width, the sample separation in narrowband TLC board, the separation is sprayed on the surface of silver sol spots, and then detected by SERS. The results show that the narrow band TLC-SERS method is simple, rapid, sensitive, can improve the conventional TLC-SERS method and two spots transverse diffusion diffusion, but also reduces the amount of fixed phase, saves the cost. This research is divided into two parts: the first part according to the literature, 1) In the preparation method of AuNPs/MIL-101 composite materials, and composite materials and silica gel are mixed in certain proportion and preparation of eTLC board; by Luo Danming 6G as a probe molecule, the mixing ratio, type and concentration of wetting agent, Raman detection parameters, to explore and determine the eTLC board signal reproducibility and stability, eTLC-SERS has been successfully established analysis of technology, and use eTLC-SERS analysis technology to build on TLC after the separation of overlapping spots is not visible spots and compounds were detected.2) the second part, the preparation of narrowband TLC plate, and then combining with the SERS technology, a narrowband TLC-SERS analysis method, and the effects of the amount of stationary phase, sensitivity, detection limit and other factors. The results of this study are as follows: 1) the preparation of SERS to enhance the performance of the best, uniformity and stability of the eTLC board; 2) to establish a eTLC-SERS method to determine the optimum SERS detection conditions, the type of wetting agent for salt Acid concentration of 0.01 mol/L, Volume 5 L, Raman laser power is 90 mW, the integration time is 5 s; 3) was detected by eTLC-SERS TLC after the separation of spot overlap and spots invisible compounds, able to identify overlapping spots components and find out the exact spot indeed completely invisiable cutting position, realizes the spot overlapping spots is not visible and compound compounds is simple, rapid and sensitive detection; 4) prepared by narrowband TLC board, a narrowband TLC-SERS method. Compared with the conventional TLC-SERS method, the sensitivity of the method is higher, lower detection limit, and the amount of stationary phase of only conventional TLC board 8%. for the first time successfully established the eTLC-SERS analysis method, and used for detecting spot overlap and spots invisible compounds. The results show that the method without external interference, metal sol substrate has the advantages of simplicity, high sensitivity, strong stability and other advantages. Secondly, this study A narrowband TLC-SERS analysis method, compared with the conventional TLC-SERS method, higher sensitivity, and fixed phase consumption, saving the cost. To sum up, are established in this paper two methods of model TLC-SERS analysis to improve the shortcomings of the conventional TLC-SERS method in a certain extent, as TLC-SERS technology has injected new vitality.

【学位授予单位】：第二军医大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB33;O657

【参考文献】