新型荧光铜纳米颗粒的制备及其在环境分析中的应用

发布时间：2018-10-09 07:26

【摘要】：随着经济社会的不断进步,环境中出现了大量有毒有害的污染物,如重金属、持久性有机污染物等。因此分析和检测环境中污染物质的种类、成分、含量以及化学形态等已成为环境分析化学的重要研究内容。传统的检测手段主要有色谱法、原子吸收光谱法、电感耦合等离子体质谱法、生物芯片技术、电化学方法以及免疫学方法等。但是这些传统的方法存在检测过程繁琐、耗时长、花费高等缺点,很难实现有效、快速的分析检测,且环境中的分析检测对象往往是微量、痕量的离子和分子,还具有空间性和时间性,因此对分析方法的要求越来越高。而荧光分析法以其灵敏度高、选择性好、操作简便等优势近年来在环境分析领域得以迅速发展。本文构建了不同类型的铜纳米颗粒(CuNPs)荧光传感器,并以用于对环境和人类健康有重大影响的Hg~(2+)、Fe~(3+)和苦味酸(PA)的灵敏检测为目标做了初步的研究与探索。主要包括以下三方面的内容:(1)以D-青霉胺(DPA)为模板,抗坏血酸为还原剂合成的DPA-CuNPs作为荧光探针灵敏地检测Hg~(2+)。CuNPs的制备实验是在避光条件下进行的,且可能由于金属铜和DPA上的巯基配体之间的电荷转移,合成的DPA-CuNPs是聚集态的,发射红色的荧光。Hg~(2+)加入到DPA-CuNPs溶液中时,嗜金属性的Hg~(2+)与DPA-CuNPs上的Cu易发生结合生成复合物,从而破坏DPA上的巯基与Cu的结合力,导致聚集态的DPA-CuNPs发生分散,从而致使荧光猝灭,基于此现象,实现对Hg~(2+)的检测。同时也对实验体系的合成比例、反应时间和pH值等实验参数进行了优化,在最优条件下,考察DPA-CuNPs对Hg~(2+)浓度的线性响应以及方法的选择性,该方法对Hg~(2+)浓度的检测限为32 nM。据此,构建了测定Hg~(2+)的新方法并用于实际水样品中Hg~(2+)含量的检测,并获得令人满意的结果。(2)利用简单的一锅法,以L-组氨酸(L-His)为模板,抗坏血酸为还原剂合成的L-His-CuNPs为荧光探针实现高效、灵敏地检测Fe~(3+)。作为一个带有空d轨道的顺磁性过渡金属离子,Fe~(3+)能够通过能量或电子转移淬灭邻近荧光团的荧光。而且,Fe~(3+)具有较高的热力学亲和力,能快速螯合胺基上的氮原子,拉近了邻近的L-His-CuNPs的距离,从而分散性较好的L-His-CuNPs会发生团聚,造成荧光猝灭,由此构建了检测Fe~(3+)的新方法,并实现对自然水样中Fe~(3+)的分析测定。此外,将具有强螯合性的EDTA溶液加入到L-His-CuNPs与Fe~(3+)的混合溶液中后,发生了荧光恢复现象。由此推断,Fe~(3+)和L-His-CuNPs之间的相互作用比较弱,EDTA通过与Fe~(3+)竞争打破了Fe~(3+)与L-His分子中氨基上的氮原子的结合力,从而荧光得以恢复。同时也对实验体系的合成比例、反应时间和pH值等相关参数进行了优化,在最优条件下,考察L-His-CuNPs对Fe~(3+)浓度的线性响应以及方法的选择性,该方法对Fe~(3+)浓度的检测限为82 nM。据此,建立了测定Fe~(3+)的新体系并用于实际水样品中Fe~(3+)含量的检测,得到了较好的结果。(3)通过刻蚀法制备荧光CuNPs实现PA的创新检测。首先以柠檬酸三钠作为模板,硼氢化钠作为还原剂,合成无荧光的尺寸较大的铜纳米晶。然后利用谷胱甘肽(GSH)将铜纳米晶刻蚀后制得发射蓝色荧光的尺寸较小的水溶性CuNPs。制得的CuNPs在水介质中具有良好的稳定性,且展现出较广的pH范围的响应能力,其荧光强度会随着pH的升高而明显增强。此外,可能是由于PA和CuNPs之间的内滤效应,合成的CuNPs的荧光能被PA有效猝灭,而其它结构类似的化合物和硝基爆炸物几乎不能猝灭CuNPs的荧光。因此,所制备的CuNPs荧光探针能在水溶液中实现PA的特异性和灵敏检测,该方法对PA浓度的检测限为65 nM。据此,发展了测定PA的新方法并用于实际水样品中PA含量的检测,得到了满意的结果。
[Abstract]:With the progress of economy and society, a lot of toxic and harmful pollutants, such as heavy metals, persistent organic pollutants and so on occur in the environment. Therefore, the analysis and detection of the species, composition, content and chemical form of pollutants in the environment have become the important research contents of environmental analytical chemistry. Traditional detection methods include chromatography, atomic absorption spectrometry, inductively coupled plasma mass spectrometry, biochip technology, electrochemical methods, and immunological methods. but the traditional method has the disadvantages of complicated detection process, long time consumption, high cost and the like, is difficult to realize effective and rapid analysis detection, and therefore the requirements for the analysis method are higher and higher. The fluorescence analysis method has the advantages of high sensitivity, good selectivity, simple operation and the like, and has been rapidly developed in the field of environmental analysis. Different types of Cu nanoparticles (CuNPs) fluorescence sensors have been constructed, and the sensitive detection of Hg ~ (2 +), Fe ~ (3 +) and picric acid (PA) which have a great influence on the environment and human health have been studied and explored. The method mainly comprises the following three aspects: (1) the DPA-CuNPs synthesized with D-Penicillamine (DPA) as a template and ascorbic acid as a reducing agent are used as a fluorescent probe to sensitively detect Hg ~ (2 +). The preparation experiment of CuNPs is carried out under light protection conditions, and the resultant DPA-CuNPs are aggregated and emit red fluorescence due to charge transfer between the metal copper and the disulfide ligands on DPA. When Hg ~ (2 +) is added to the DPA-CuNPs solution, the metallic Hg ~ (2 +) binds to the Cu on DPA-CuNPs to form the complex, thus destroying the binding force between the Cd and Cu on DPA, leading to the dispersion of DPA-CuNPs on DPA, which leads to the inactivation of the fluorescence. Based on this phenomenon, the detection of Hg ~ (2 +) is realized. At the same time, the experimental parameters such as the synthesis ratio, reaction time and pH value of the experimental system were optimized. Under the optimum conditions, the linear response of DPA-CuNPs to Hg ~ (2 +) concentration and the selectivity of the method were investigated. The detection limit of Hg ~ (2 +) concentration was 32 nM. Accordingly, a new method for determination of Hg ~ (2 +) was constructed and used in the detection of Hg ~ (2 +) content in actual water samples, and satisfactory results were obtained. (2) Using a simple pot method, L-His-CuNPs synthesized by L-histidine (L-His) as a template and ascorbic acid as a reducing agent are used as a fluorescent probe to realize high-efficiency and sensitive detection of Fe ~ (3 +). As a paramagnetic transition metal ion with an empty d-orbit, Fe ~ (3 +) can quench the fluorescence of adjacent fluorophores by energy or electron transfer. Moreover, Fe ~ (3 +) has a higher thermodynamic affinity, can rapidly change the nitrogen atom on the amino group, shortens the distance of the adjacent L-His-CuNPs, so that the L-His-CuNPs with good dispersivity can be agglomerated, so that the fluorescence quenching is destroyed, thus a new method for detecting Fe ~ (3 +) is constructed. The analysis and determination of Fe ~ (3 +) in natural water samples were carried out. In addition, a fluorescence recovery phenomenon occurred after the EDTA solution with strong affinity was added to the mixed solution of L-His-CuNPs and Fe ~ (3 +). It is concluded that the interaction between Fe ~ (3 +) and L-His-CuNPs is weak. EDTA has broken the binding force between Fe ~ (3 +) and N atom in L-His molecule by competition with Fe ~ (3 +), so that fluorescence can be recovered. At the same time, the synthesis ratio, reaction time and pH value of the experimental system were optimized. Under the optimum conditions, the linear response of L-His-CuNPs to the concentration of Fe ~ (3 +) and the selectivity of the method were investigated. The detection limit of the method on the concentration of Fe ~ (3 +) was 82 nM. Therefore, a new system for determination of Fe ~ (3 +) was established and used in the detection of Fe ~ (3 +) in actual water samples. (3) preparing the fluorescent CuNPs through an etching method to realize the innovative detection of the PA. firstly, sodium citrate is used as a template, sodium borohydride is used as a reducing agent, and copper nanocrystals without fluorescence are synthesized. and then the copper nanocrystalline is etched by using glutathione (GSH) to produce water-soluble CuNPs which emit blue fluorescence. The prepared CuNPs have good stability in aqueous medium, and exhibit a broader pH range response capability, whose fluorescence intensity will be significantly enhanced as the pH increases. In addition, the fluorescence energy of the synthesized CuNPs can be effectively extinguished by the PA due to the internal filtration effect between the PA and the CuNPs, while other structurally similar compounds and nitro explosives can hardly destroy the fluorescence of the CuNPs. Therefore, the prepared CuNPs fluorescent probe can achieve the specificity and sensitive detection of PA in aqueous solution, which limits the detection limit of PA concentration to 65 nM. Based on this, a new method for measuring PA was developed and used in the detection of PA in actual water samples, and satisfactory results were obtained.
【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O657.3;TP212;X830

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