光谱法结合纳米材料用于环境中危险物质的检测

发布时间：2018-10-25 14:59

【摘要】：本论文利用了三种不同的纳米材料构建了三种光谱传感器,把纳米材料作为比色或荧光探针,并结合酶催化法、紫外可见光谱法以及荧光猝灭法等方法对环境中常见的危险物质(汞离子、有机磷农药)进行了定量分析。该类方法操作简单,检测快速,灵敏度高,为纳米材料在危险物质的定量检测方面提供了一些新的思路。具体内容总结如下:阐述了银纳米粒子、石墨烯量子点、金纳米簇、四氧化三铁这几种纳米材料的发展、其常见的合成方法以及在分析化学研究领域的应用研究;介绍了几种检测对象的用途、现状;展望了纳米材料结合分子光谱法在分析检测领域的一些动向。利用硼氢化钠还原硝酸银的方法制备了柠檬酸钠保护的银纳米粒子。利用紫外-可见光谱、透射电子显微镜和能量弥散X射线能谱等表征手段对合成的银纳米粒子的形貌及其在反应前后的聚散程度进行表征。(1)乙酰胆碱酯酶催化底物硫代乙酰胆碱水解产生的硫代胆碱可以和银纳米粒子结合使其聚集;(2)这种变化会反应在体系溶液的颜色上,银纳米溶液由亮黄色变成粉红色;(3)有机磷或氨基甲酸酯农药能使乙酰胆碱酯酶变性失活,从而抑制这一变化的发生。依据此原理对有机磷或氨基甲酸酯农药的含量进行测定。通过将柠檬酸在200?C下热解合成了石墨烯量子点,在450 nm处可以发出蓝色荧光。(1)通过静电作用,带正电的汞离子会吸附在带负电的石墨烯量子点表面诱导其聚集,同时通过电荷转移使其荧光猝灭;(2)继续加入半胱氨酸后,汞离子会与其通过金属巯基键结合从而脱离石墨烯量子点表面,荧光恢复。因此根据以上荧光先猝灭后增强的变化可以构建一个依次检测汞离子和半胱氨酸的高灵敏荧光传感器。我们将磁性四氧化三铁和金纳米簇结合,合成了一种磁性的荧光纳米复合材料,四氧化三铁的核被包裹在一层二氧化硅中,外表面再修饰上一层氨基;将牛血清白蛋白保护的金纳米簇进行羧基活化;通过肽键,它们可以结合在一起并形成一种交联结构。6-巯基嘌呤会吸附在金纳米簇的表面并诱导其聚集产生更大的金纳米粒子,破坏这种交联结构,同时荧光猝灭。根据此原理可以构建一个6-巯基嘌呤的荧光传感器。本文的创新点如下:1.利用了3种不同类别的纳米材料对一些环境中的危险物质及药物进行了定量检测,都取得了非常理想的实验结果,具有很高的灵敏度和较好的选择性;2.构建的定量方法相对传统的检测方法操作简单、检测快速,具有更强的实际应用能力;3.通过先猝灭后增强的荧光“On-Off-On”体系构建了同时检测汞离子和半胱氨酸的双传感器;4.结合理论,自行构建了纳米复合材料的合成方法,成功将金纳米簇和四氧化三铁纳米粒子两种纳米材料的性质整合到一起,大大提高了检测效率。
[Abstract]:In this paper, three kinds of spectrum sensors were constructed by using three different nanomaterials, which were used as colorimetric or fluorescent probes, and combined with enzymatic catalysis. UV-Vis spectroscopy and fluorescence quenching methods were used to quantitatively analyze the common hazardous substances (mercury ions, organophosphorus pesticides) in the environment. This method is simple in operation, rapid in detection and high in sensitivity. It provides some new ideas for quantitative detection of hazardous substances by nanomaterials. The specific contents are summarized as follows: the development of silver nanoparticles, graphene quantum dots, gold nanoclusters, iron trioxide, their common synthesis methods and their applications in analytical chemistry are reviewed. The applications and present situation of several detection objects are introduced, and some trends of nanomaterials combined with molecular spectroscopy in the field of analysis and detection are prospected. Silver nanoparticles protected by sodium citrate were prepared by reducing silver nitrate by sodium borohydride. Using the UV-Vis spectrum, Transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) were used to characterize the morphology of the synthesized silver nanoparticles and their degree of dispersion before and after the reaction. (1) acetylcholinesterase catalyzed the hydrolysis of thioacetylcholine by acetylcholinesterase. The resulting thiocholine can be combined with silver nanoparticles to aggregate it; (2) this change is reflected in the color of the solution. Silver nanoparticles changed from bright yellow to pink. (3) organophosphorus or carbamate pesticides could deactivate acetylcholinesterase and inhibit this change. According to this principle, the content of organophosphorus or carbamate pesticides was determined. Graphene quantum dots were synthesized by pyrolysis of citric acid at 200C, and blue fluorescence could be emitted at 450 nm. (1) by electrostatic action, positively charged mercury ions would be adsorbed on the surface of negatively charged graphene quantum dots to induce their aggregation. At the same time, the fluorescence was quenched by charge transfer. (2) after the addition of cysteine, mercury ions would bind to the surface of graphene quantum dots through metal sulfhydryl bonds, and the fluorescence would recover. Therefore, a highly sensitive fluorescence sensor for the detection of mercury ion and cysteine can be constructed according to the changes of fluorescence quenching and then enhancement. A kind of magnetic fluorescent nanocomposites was synthesized by combining magnetic ferric oxide with gold nanoclusters. The core of Fe _ 2O _ 3 was encapsulated in a layer of silica, and the outer surface was modified with a layer of amino. The bovine serum albumin protected gold nanoclusters are activated by carboxyl groups; by peptide bonds, they can bind together and form a cross-linking structure. 6-mercaptopurine adsorbs on the surface of the gold nanoclusters and induces their aggregation to produce larger gold nanoparticles. The crosslinking structure was destroyed and the fluorescence quenching was carried out at the same time. According to this principle, a 6-mercaptopurine fluorescence sensor can be constructed. The innovations of this paper are as follows: 1. Three different kinds of nanomaterials were used to quantitatively detect some dangerous substances and drugs in the environment. All of them obtained very ideal experimental results with high sensitivity and good selectivity. 2. Compared with the traditional detection method, the quantitative method constructed is simple, rapid and has stronger practical application ability. 3. A double sensor for the simultaneous detection of mercury and cysteine was constructed by quenching and then enhancing the fluorescence "On-Off-On" system. 4. Combining with the theory, the synthesis method of nanocomposites was constructed, and the properties of gold nanoclusters and iron trioxide nanoparticles were successfully integrated together, which greatly improved the detection efficiency.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X830;TB383.1

【共引文献】