基于局域表面等离子体共振光谱可视化传感器在环境分析中的应用

	基于局域表面等离子体共振光谱可视化传感器在环境分析中的应用
	张志阳
学位类型	硕士
导师	陈兆鹏
	2014-06-26
学位授予单位	中国科学院研究生院
学位授予地点	北京
学位专业	海洋化学
关键词	金纳米粒子/纳米棒局域表面等离子体共振免标记比色传感器环境分析
摘要	工业的不断发展使得环境污染问题变得越来越严重，环境污染物对人类的健康造成了巨大的威胁。因此，发展简单的并且可以广泛使用的环境污染物的现场分析方法显得极为迫切。由于其独特的局域表面等离子体共振 (LSPR)性质，贵金属纳米粒子（尤其金纳米粒子）已被广泛用于构建适于环境和生物检测的光化学传感。然而，目前构建的传感器仍然存在着明显的不足，如低灵敏度，不适合复杂样品等。本论文着眼解决或改善这些问题，发展了一系列基于局域表面等离子体共振光谱的化学/生物传感器，并利用这些传感器成功地实现了环境污染物在环境样品中的高灵敏检测。 1．基于距离依赖的局域表面等离子体共振光谱性质比色传感器（1）提出了一种基于诱导金纳米粒子团聚的二价钴离子免标记比色传感方法。硫代硫酸根稳定的金纳米粒子能够稳定存在于高盐溶液。在有乙二胺 (en) 存在时，二价钴离子被溶解氧氧化为Co(en)₃³⁺，生成的Co(en)₃³⁺ 进而与金纳米粒子表面吸附的硫代硫酸根结合，引起金纳米粒子表面所带负电荷下降，使得金纳米粒子发生团聚，溶液颜色也从红色变为蓝色。利用这一现象实现了钴离子高灵敏高选择检测（检出限为0.04 μM）。（2）利用吐温20稳定的金纳米粒子，开发出了硫氰酸根的检测试剂盒。吐温20包覆的金纳米粒子可以稳定存在于高盐缓冲液中。由于硫氰酸根和金纳米粒子具有非常强的结合能力，它能够取代金纳米粒子表面的吐温20使得金纳米粒子发生聚集，颜色由红色变为蓝色。利用这一变化，开发出了一种硫氢酸根比色法检测试剂盒。此试剂盒成功实现了人体唾液中的硫氰酸盐的检测，结果显示抽烟人群和非抽烟人群唾液中的硫氰酸根存在明显差异。（3）基于硫离子可增加金纳米粒子的稳定性的性质，提出了一种空气中硫化氢的可视化检测方法。硫化氢气样能有效地被碱性缓冲液吸收，并以硫氢酸根（HS^-）的形式存在于溶液中。当金纳米粒子加入到溶液中时， HS^-与金纳米粒子表面的金原子作用并在金纳米粒子表面生成大量[Au⁺][S^2-]，从而增加了金纳米粒子的稳定性并使其可在高盐溶液依然保持酒红色。而在没有硫化氢时，金纳米粒子会发生聚集，溶液变为蓝色。根据这一现象可以可视化的检测空气中的H₂S气体。本方法对H₂S气体的肉眼检测下限为0.5 ppm。 2, 基于形貌依赖的局域表面等离子体共振光谱性质比色传感器（1）基于氧化刻蚀金纳米棒的原理发展了一种亚硝酸盐比色传感器。在强酸溶液中，溶解氧对金纳米棒的氧化刻蚀非常缓慢，因此金纳米棒的形貌变化很小，金纳米棒LSPR吸收峰和颜色几乎不变。当有亚硝酸盐存在时，亚硝酸根可以氧化刻蚀金纳米棒使其长径比迅速减小，导致纳米棒LSPR吸收发生较大的蓝移，溶液逐渐由蓝色向红色转变。我们利用这一现象发展了一种高灵敏的亚硝酸盐比色传感器，检出下限可达0.4 μM。利用这一方法，我们实现了饮用水中亚硝酸的定量检测。（2）基于铜离子催化刻蚀金纳米棒的原理，开发出了一种高灵敏的铜离子比色检测方法。在十六烷基三甲基溴化铵存在下，铜离子可以催化氧化金纳米棒沿着轴向方向刻蚀，最终导致金纳米棒的LSPR吸收峰的蓝移，伴随着溶液颜色由蓝色向红色转变。通过了一系列实验阐述了铜离子催化刻蚀金纳米棒原理。借助这一现象，我们发展了一种灵敏的铜离子比色传感器（检测下线为0.5 nM），同时我们又将这一方法开发成铜离子检测试纸条。重要的是此传感器具有非常好的特异性和抗干扰能力，使其可应用于复杂样品（如海水）铜离子的检测。（3）利用“类Fenton反应”催化刻蚀金纳米棒实现了钴离子的可视化检测。在碳酸盐存在条件下，钴离子可与过氧化氢发生“类Fenton反应”，催化产生大量具有强氧化性的超氧阴离子；超氧阴离子进一步氧化刻蚀金纳米棒使其长径比变小。金纳米棒LSPR吸收峰发生蓝移，颜色由蓝色变为红色。利用这一原理发展的钴离子传感器具有较好的灵敏度和选择性。重要的是，这一新原理提供了一种设计基于对纳米粒子刻蚀作用的传感器的新思路。
其他摘要	With the rapid development of industry, the environmental problems become more and more urgent and environmental pollutants have posed a serious threat to human health. And thus, developing the quick and on-site detection methods for environmental pollutants is being urgently needed. Noble metal nanoparticles（especially gold nanoparticles） possess their unique localized surface plasmon resonance (LSPR) optical property and thus have been widely used in environmental and biological analysis. However, most of them exists obvious disadvantages, such as unsatisfied sensitivity and inapplicability in high salt matrix. In this thesis, taking the solving and improvement of theses disadvantages as the starting point, we have proposed a list of chemo-sensors or biosensors based on LSPR spectroscopy, by which many pollutants have been sensitively detected, even in sea water. 1, Colorimetric sensors based on the distance-dependent LSPR optical property (1) A label-free method for sensing Co²⁺ in aqueous solutions was described. The target was achieved by the inducing aggregation of thiosulfate (S₂O₃^2-) stabilized gold nanoparticles (AuNPs) in the presence of ethylenediamine (en). Co²⁺ first reacted with en and formed complexes of Co(en)₃²⁺ in aqueous solutions, which was followed by the oxidation Co(en)₃²⁺ to Co(en)₃³⁺ by dissolved oxygen. Co(en)₃³⁺ then attacked S₂O₃^2- ligands adsorbed on AuNPs’ surfaces, which reduced the surface charges of AuNPs and induced the aggregation of AuNPs. The process was accompanied by a red-shift in the adsorption spectrum and a visible color change from wine red to blue. The proposed method is sensitive (LOD = 0.04 μM) and selective over other metal ions except for Cu²⁺) toward Co²⁺. (2) A simple, sensitive and selective colorimetric detection method for thiocyanate (SCN^-) has been developed by using Tween 20-stabilized gold nanoparticles. In the structure of Tween 20-AuNPs, Tween 20 coating shields citrate-capped AuNPs’ surface and thus makes citrate-capped AuNPs stable in high ionic strength solution. Because of the high affinity between SCN^- and Au, SCN^- can displace the citrate and Tween 20 adsorbed on the Au surface, resulting in the aggregation of AuNPs along with a color change from red to blue, which could be perfectly used to determinate the concentration of SCN^- by a UV-vis spectrophotometer or even naked eyes. Using this method, we successfully detect the SCN^- in the tap water and saliva. (3) We have described a simple and low-cost method for on-site detection of hydrogen sulfide (H₂S) in air, which is based on the anti-aggregation of gold nanoparticles (AuNPs). H₂S will initially dissolve in the solution and mainly exist as hydrosulfide ions (i.e. HS^-) due to the acid/base equilibrium. As soon as the AuNPs solution is added into the above solution to act as the indicator, the Au atoms at the surfaces of AuNPs will be oxidized by dissolved oxygen in the presence of HS^- and generated large numbers of [Au⁺][S^2-] on the surfaces of AuNPs, The generated [Au⁺][S^2-] will significantly enhance colloidal AuNPs’ stability, as a result, AuNPs solution can remain wine red in color regardless of high salt. In contrast, without bubbling of H₂S, AuNPs aggregate and change from red to blue. According to this phenomenon, the proposed method exhibits an excellent visual sensitivity with a naked-eye detectable limit of 0.5 ppm (v/v). 2, Colorimetric sensors based on the shape-dependent LSPR optical property (1) A simple colorimetric method was developed for sensing of nitrite based on etching of gold nanorods. In strong acidic solution, gold nanorod can be oxidized by the dissolved oxygen slowly and thus its LSPR absorption peak change little. In the presence NO₂^-, gold nanorod is etched along the longitudinal direction, accompanied by shape changes in aspect ratios (length/width), leading to a blue shift of LSPR absorption peak. As a result, the solution color alter from bluish green to red and then to colorless with increase of nitrite. This method exhibits a good sensitivity（LOD = 0.4 μM） and a satisfied selectivity. The practical performance of the proposed method was further tested by samples of local drinking water. (2) We have developed a novel approach for the rapid visual detection of Cu²⁺ in natural samples based on copper-mediated leaching of gold nanorods (GNRs). In the presence of hexadecyltrimethylammonium bromide, the GNRs are preferentially etched by Cu²⁺along the longitudinal direction. And as a result, the localized surface plasmon resonance (LSPR) absorption peak shifts to short wavelength, accompanied by a color change from blue to red. The mechanism has been carefully discussed by a series of control experiments. Under the optimal conditions, this sensor exhibits a good sensitivity (LOD = 0.5 nM). In addition, such a nanoparticle-based sensor is also successfully applied to test paper for the visual detection of Cu²⁺. Most importantly, the approach is highlighted by its high selectivity and tolerance to interference, which enables the sensor to detect Cu²⁺ directly in complex matrix, especially in seawater. (3) A new visual method for detection of cobalt(II) based on etching of gold nanorods via mediation of Fenton-like reaction was proposed. After solution containing Co²⁺was injected into the mixture of bicarbonate (HCO₃^-) and hydrogen peroxide(H₂O₂), the Fenton-like reaction will happen and produce a large amount of superoxide radical (O₂^▪-). Then, gold nanorods were oxidized to Au⁺ ions by the O₂^▪-accompanied by shape changes, leading to an obvious colour change from green to red. This change is proportional to the concentration of Co²⁺ and could be quantified by naked eyes or a UV–vis spectrometer. This method provided a highly sensitive (LOD = 1.0 nM) and selective detection toward Co²⁺. The principle of etching of gold nanoparticles provides a strategy for design of new nanoparticles-etching-based sensors.
语种	中文
文献类型	学位论文
条目标识符	http://ir.yic.ac.cn/handle/133337/6814
专题	中国科学院烟台海岸带研究所知识产出_学位论文
推荐引用方式 GB/T 7714	张志阳. 基于局域表面等离子体共振光谱可视化传感器在环境分析中的应用[D]. 北京. 中国科学院研究生院,2014.

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