卤素离子修饰贵金属纳米材料检测痕量硝基类爆炸物的研究

发布时间：2019-03-06 07:58

【摘要】：随着硝基芳香类爆炸物在军事和民间的应用逐渐广泛,其对环境造成的污染也日益显露。爆炸物在生产、制造与运输的过程中难免会发生泄露,残留在土壤与水环境中的爆炸物成分不仅危害环境,还会间接地对人类的生命健康造成威胁。另外,爆炸物是恐怖主义危害社会稳定与人民安全的最直接手段,因而爆炸物的检测也是反恐与维稳工作的重点。近年来,表面增强拉曼光谱(SERS)技术因其具有可便携、分析速度快和高灵敏度等优点,已经成为检测爆炸物最重要的光谱方法之一。其中,具有超高灵敏度的SERS基底是SERS技术实现微痕量爆炸物成功检出的前提。因此,本论文研发了一种简单、省时、低成本的方法制备超高灵敏度SERS基底并实现硝基类爆炸物的检测。首先,为了提高SRES基底的灵敏度,本论文选用化学试剂修饰纳米粒子的方法,制备具有超高灵敏度的SERS基底。在实验中通过对纳米粒子种类、化学试剂以及制备条件等优化,最终获得了 SERS基底的制备方法:1 mL的AgNPs(还原剂为柠檬酸三钠)离心浓缩得5 μL左右纳米粒子浓缩胶体,再加入25 μL的KI(10 mM)溶液混匀,在避光条件下反应20 min获得Ag IMNPs基底。在波长为632.8 nm的激发光条件下检测了硝基类爆炸物TNT和2,4-DNT。结果表明:碘离子修饰后的银纳米粒子具有良好的SERS活性,2,4-DNT和TNT的最低检出浓度为0.1 nM,换算为质量的检出限分别约为0.364 pg和0.454 pg。然后,本论文尝试探讨了 AgIMNPs基底的增强机理,结果表明AgIMNPs基底的增强机理有两个方面的原因。其一,本文在对Ag NPs的紫外扫描中发现,KI修饰AgNPs会使其最大紫外吸收波长发生红移,这可能是因为KI使AgNPs团聚,而这种团聚能够使爆炸物的SERS信号得到增强。其二是KI对Ag NPs表面杂质的清除作用,在纳米粒子的表面产生了更多的"空位",为爆炸物分子与纳米粒子表面的接触提供了更多的机会。在这两种增强机制的共同影响下,AgIMNPs较AgNPs的灵敏度得到了大幅度的提升。而且Ag IMNPs基底对多种硝基类芳香族化合物都有不同程度的增强效果,这表明AgIMNPs基底能适用于多种硝基类爆炸物的快速检测。由于AgIMNPs基底的高灵敏度,将其与他材料联用能够扩大其在环境监测、安检工作以及食品安全等领域的应用。
[Abstract]:With the wide application of nitroaromatic explosives in military and civilian fields, the environmental pollution caused by nitroaromatic explosives is becoming more and more obvious. Explosives will inevitably leak in the process of production, manufacture and transportation. The explosive residues in the soil and water environment will not only harm the environment, but also indirectly threaten the life and health of human beings. In addition, explosives are the most direct means of terrorism to endanger social stability and people's security, so the detection of explosives is also the focus of counter-terrorism and maintenance of stability. In recent years, surface-enhanced Raman spectroscopy (SERS) has become one of the most important spectral methods for detecting explosives due to its portability, high analytical speed and high sensitivity. Among them, the SERS substrate with ultra-high sensitivity is the prerequisite for the successful detection of micro-trace explosives by SERS technology. Therefore, this paper develops a simple, time-saving and low-cost method to prepare ultra-high sensitivity SERS substrates and realize the detection of nitroexplosives. Firstly, in order to improve the sensitivity of SRES substrate, the SERS substrate with ultra-high sensitivity was prepared by chemical reagent modification. In the experiment, the preparation method of SERS substrate was obtained by optimizing the kinds of nanoparticles, chemical reagents and preparation conditions. The preparation methods were as follows: (1) AgNPs (reducing agent was trisodium citrate) centrifugally concentrated 5 渭 L nanoparticles concentrated colloid; After mixing with 25 渭 L KI (10 mM) solution, the Ag IMNPs substrate was obtained by the reaction of 20 min under the condition of avoiding light. Nitroexplosives TNT and 2,4-DNT were detected at a wavelength of 632.8 nm. The results showed that the silver nanoparticles modified by iodine ion had good SERS activity. The detection limits of the minimum detection concentrations of 2,4-DNT and TNT were about 0.364 pg and 0.454 pg., respectively. The detection limits were about 0.364 pg and 0.454 pg., respectively. The detection limits of the silver nanoparticles modified by iodine ion were about 0.364 pg and 0.454 pg., respectively. Then, the enhancement mechanism of AgIMNPs substrate is discussed in this paper. The results show that there are two reasons for the enhancement mechanism of AgIMNPs substrate. First, in the UV scanning of AgNPs, it is found that the maximum UV absorption wavelength of AgNPs modified by KI is red-shifted, which may be due to the aggregation of AgNPs by KI, which can enhance the SERS signal of explosives. The other is the removal of impurities on the surface of Ag NPs by KI, which creates more "vacancies" on the surface of nano-particles, which provides more opportunities for the contact of explosive molecules with the surface of nano-particles. Under the influence of these two enhancement mechanisms, the sensitivity of AgIMNPs is greatly improved than that of AgNPs. Moreover, AgIMNPs substrates have different enhancement effects on various nitro aromatic compounds, which indicates that AgIMNPs substrates can be used for the rapid detection of various nitroexplosives. Due to the high sensitivity of AgIMNPs substrate, its application in environmental monitoring, security inspection and food safety can be expanded by combining it with other materials.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ560.72;TB383.1;O657.37

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