【作者】 温雅娟；

【导师】 王煜；

【作者基本信息】 山西大学 ， 分析化学， 2012， 硕士

【摘要】 第一章首先介绍了荧光探针的分类及其响应机制。之后对量子点(QDs)的光学性质进行了概述,并就其在分析化学方面的应用进行了综述。第二章采用一种简便的方法制备了水溶性的巯基丁二酸(MSA)包覆的CdSe QDs (MSA-CdSe QDs),同时利用紫外光谱、荧光光谱、红外光谱等手段对合成的水相量子点进行了表征。结果表明,巯基丁二酸可部分替换量子点表面原有的油酸配体、通过其硫原子上的非键电子对与悬挂的Cd2+配位结合,形成巯基丁二酸包覆的量子点。且对原有结构改变不大,该复合物仍可发射荧光,并具有水溶性。鉴于巯基丁二酸的特性,合成的MSA-CdSe-QDs应该具有络合金属离子的识别功能,从而可以作为一种新型的识别金属离子的荧光传感器。第三章考察了常见金属离子对巯基丁二酸包覆的CdSe QDs(MSA-CdSe QDs)的荧光响应。在中性PBS缓冲溶液中,Cd2+可以增强该量子点的荧光,Cu2+则对该量子点具有荧光猝灭效应,并且在各自的浓度范围内同量子点的相对荧光强度呈现良好的线性关系,由此可实现对这两种金属离子的识别与检测。初步探讨了金属离子对量子点的响应机理。第四章以7-硝基苯并-2-氧杂-1,3-二唑为荧光团,二乙醇胺为配体合成了新的荧光探针NBD-OH。在中性缓冲水溶液中,VB12可以使NBD-OH荧光发生猝灭,由此建立了一种新的检测VB12的荧光方法。实验结果表明,在优化的实验条件下,当VB12的浓度在0.0-2.4×10-5M范围时,其浓度同体系荧光变化△F呈现良好的线性关系,检测限为8×10-8M。该方法可用于实际样品VB12针剂及片剂的检测。第五章非除氧条件下,在y-环糊精(y-CD)溶液中,α-溴代萘(α-BrN)可以敏化樟脑醌(CQ)产生强的室温磷光。考察了y-CD浓度、α-BrN浓度、CQ浓度等因素对体系磷光强度的影响。实验发现VB12的加入对体系的磷光强度具有猝灭作用,由此建立了对VB12的新的磷光检测方法。更多还原

【Abstract】 Chapter1The classification and mechnism of fluorescent probes are briefly introduced. The optical properties of quantum dots and their analytical applications have been reviewed.Chapter2Water-soluble luminescent CdSe quantum dots surface-modified with mercaptosuccinic acid (MSA-CdSe-QDs) were prepared and characterized by UV-vis and fluorescence spectroscopy, FT-IR, and TEM techniques. The results show that the sulfur atom of MSA coordinate with Cd2+ion on the QD surface and partially replaced the original oleic acid. After the MSA modification, the QDs exhibited no obvious change in shape or size. Due to the metal ion binding capability of MSA, the synthesized QDs could potentially function as a fluorescent probe for metal ions.Chapter3The sensing behavior of MSA-CdSe-QDs towards metal ions was investigated by fluorescence spectroscopy. It was found that in neutral PBS buffer solution, Cd2+enhanced the fluorescence of the QDs, whereas Cu2+exhibited a significant quenching effect on the fluorescence of the QDs. The fluorescence responses were concentration-dependent, which could be used for recognition of Cu2+ions and Cd2+in aqueous solution. The possible mechanism was also discussed.Chapter4A new fluorescent probe,4-N, N-di (2-hydroxyethyl) imino-7-nitrobenzo-2-oxa-1,3-diazole (NBD-OH) was synthesized in a single step with reasonably good yield. It was found that Vitamin B12(VB12) had the ability to quench the fluorescence of NBD-OH, and the quenched fluorescence intensity was proportional to the concentration of VB12. A method for VB12determination based on the quenching fluorescence of NBD-OH was thus established. Interference effects of various substances including sugars, vitamins, amino acids, inorganic cations and some organic substances have been studied. Under optimal conditions, the linear range is0.0-2.4×10-5M. The determination limit is8.3×10-8M. The method was applied to measure VB12injections and tablets with satisfactory results.Chapter5α-bromonaphthalene (α-BrN) has been used as a donor of triplet state energy for the acceptor camphorquinone (CQ) in y-cyclodextrin nanocavity. Intense RTP phosphorescence emission of CQ was observed in non-deoxygenated γ-CD solution. Several parameters that affect the intensity of sensitized phosphorescence have been examined. It was found that Vitamin B12(VB12) had the ability to quench the phosphorescence of CQ, and the quenched RTP intensity was proportional to the concentration of VB12. A method for VB12determination based on the phosphorescence quenching of CQ was thus established.更多还原