【作者】 林东岳；

【导师】 刘锦淮；

【作者基本信息】 安徽大学 ， 生物化学与分子生物学， 2013， 硕士

【摘要】 随着生产技术的不断进步,化学爆炸物三硝基甲苯(2,4,6-trinitrotoluenc, TNT)越来越多的应用于矿产开采、军事安全以及国防工业等领域。与此同对,也带来了一些负面影响,即对周围的环境造成了一定程度的污染,对人们的生活也形成了潜在的威胁。近年来,针对高效TNT检测方法的探索已经成为一个研究热点。比色法检测爆炸物TNT以其简单、直观、高选择性的特点进入人们的视野。该方法主要是利用金纳米颗粒构建光学探针,进而产生一个肉眼可见的颜色变化来实现对分析物检测的目的。另外,在基于纳米颗粒比色法的基础上,表面增强拉曼散射(SERS)技术以其高灵敏的指纹图谱分析被人们所特别关注。基于贵金属纳米材料的SERS检测TNT新方法开始出现,并取得了很好的检测效果。通常情况下,研究者们都是通过构建SERS探针传感器或者利用特定的SERS基底来实现对TNT的痕量检测。目前,利用纳米材料传感器检测TNT的发展进度迅速,但是；也存在一些问题：(1)光学探针检测TNT的抗环境干扰能力不高,其检测限有待进一步提高。(2)SERS检测TNT的重复性与稳定性较差,有待提高。(3)增强效果突出的理想SERS基底的制备方法还不够完善,需要继续探索。本论文围绕上述几个问题开展了相关研究,主要的研究内容如下：第一,利用乙二胺(EDA)对金纳米颗粒(Au NPs)进行化学修饰,构建用于检测爆炸物TNT的EDA包裹的AuNPs (Au Ps@EDA)光学探针,该光学探针具有简单、稳定、低成本、高灵敏性以及低检测限的特点,能够实现对TNT的痕量检测。其中,Au NPs@EDA超灵敏比色探针在水溶液中可以检测到400pM水平的TNT。另外,利用紫外-可见(UV-vis)吸收光谱仪以及动态光散射(DLS)仪,可以分别实现40pM和0.4pM水平的TNT超灵敏检测。第二,通过表面增强共振拉曼散射(SERRS)的方法对TNT进行了快速、灵敏的检测。利用亚硫酸钠(Na2SO3)对TNT分子进行磺化,增加其亲水性,使其能够与氯代十六烷基吡啶包裹的银纳米颗粒(AgNPs@CPC)基底牢固的结合。使用表面活性剂CPC对TNT分子进行增敏,提高其SERS散射截面面积。通过形成的TNT-SO3-CPC复合物,对TNT的检测限能达到5×10-11M,并且该SERRS检测过程可以在5min内完成。同时,还考察了该方法对TNT检测的重复性及稳定性,扩展了SERRS或SERS快速检测TNT的应用前景。第三,针对SERS检测TNT的新型基底的制备,我们采用一步法首次制备了新型DNA-Au复合SERS基底。通过原位光还原方法在DNA的骨架结构上形成了Au NPs。该新型的纳米复合结构活性基底表现出了很好的SERS信号增强效果,并且能够实现对纳米结构间隙的有效调控。此外,该复合基底合成过程简单、快速,只需约15min。该DNA-Au复合结构作为SERS基底在TNT的检测领域具有潜在的应用价值。’通过上述研究,利用合适的贵金属基底,通过SERS或SERRS方法可以实现对爆炸物TNT及有机污染物的痕量检测。推动了SERS方法在分析化学、环境检测领域的深入应用,并扩展了SERS研究用于现场检测的可行性。更多还原

【Abstract】 With the development in both production and social life activities, the chemical explosive2,4,6-trinitrotoluene (TNT) was more and more used in the fields of mining, military security, and national defense industry, etc. However, many negative effects were caused with regard to the pollution of environment or the potential threat to human health. In recent years, the rapid and sensitive detection of TNT has become a hot topic and attracted more and more attentions in the research field. With the merits of simpleness, intuition, high selectivity of detecting the TNT explosive, the colorimetry has come into the researchers’ vision. This method is mainly based on the ligand-capped nanoparticles optical probe, which produces a visible color change to achieve the sensing of target analytes. In addition, on the basis of colorimetric method, surface enhanced Raman scattering (SERS) is the widely used technique because of its high sensitivity and the fingerprint analysis. Currently, the development of novel nano-materials sensor for TNT detection progressed fast, nevertheless there are still some bottlenecks with regard to (1) Environmental interference resistance ability of the optical probe detection of TNT is not high; its detection limit needs to be further improved.(2) The repeatability and stability of SERS measurements is very poor and remains to be further improved.(3) Enhancement effect of SERS substrate is not perfect and needs to continue to explore. This paper focused on these several problems and the main research contents are as follows:1) The use of ethylenediamine (EDA) for chemical modification of gold nanoparticles (Au NPs) constructed a novel optical probe for detecting the TNT explosive. This Au NPs@EDA optical probe has several advantages with regards to simplicity, stability, low cost, high sensitivity, and the low detection limit, which can realize the trace detection of TNT. Among them, the Au NPs@EDA ultrasensitive colorimetric probe in aqueous solution can be detected in the400pM levels of TNT. In addition, the use of ultraviolet-visible absorption spectrometer and dynamic light scattering (DLS) instrument can implement40pM and0.4pM levels of TNT ultrasensitive detection.2) A novel SERRS platform for fast and sensitive detection of TNT was developed. A cationic surfactant, cetylpyridinium chloride (CPC) was modified on the surface of silver sols (CPC-capped Ag). CPC not only can act as the surface seeking species to trap sulfite-sulfonated TNT, but also undergoes complexation with it, causing the arising of two charge-transfer bands at467and530nm, respectively. This chromophore absorbs the visible light that matches with the incident laser and plasmon resonance of Ag sols by the use of a532.06nm laser, and offered a highly resonance Raman enhancement. This SERRS platform evidenced a fast and accurate detection of TNT with a detection limit of5×10-11M under a low laser power (200μW) and a short integration time (3s). The CPC-capped Ag also provides remarkable sensitivity and reliable repeatability.3) A one-step synthesis and controlled assembly of Au nanoparticles (NPs) on X.-DNA scaffolds by an in-situ photoreduction method was developed aimed at the TNT sensing. The interpaticle gaps of the Au NPs attached on DNA can be fine regulated by controlling the R values (denoted as the ratio of Au (Δ) ions added per DNA base pairs). Empirical enhancement factor above1×109is observed when the R value is in a fairly broad range of10-60under785nm excitation. Moreover, this substrates have a good reproducibility at different sites on a substrate, with a standard deviation of<15%. These results indicate that the photoreduced Au NPs on DNA scaffolds can be used as SERS-active substrates which exhibit high and reproducible SERS activity. This DNA-Au hybrid has potential applications in chemical and biological SERS analysis. Through the above researches, several optical nanoprobes were developed and realized the trace detection of TNT, and these probes have a great application prospect in the field of analytical chemistry, environmental analysis.更多还原