【作者】 吴玉芹；

【导师】 朱昌青；

【作者基本信息】 安徽师范大学 ， 分析化学， 2005， 硕士

【摘要】 花菁染料具有摩尔吸收系数大和荧光量子产率高的优点, 采用红区测量可有效地排除背景干扰,获得更为理想的分析灵敏度和选择性。花菁的光谱对外界微环境的变化极为敏感,非常适合生物及环境样品的分析研究。事实上,花菁目前已成为荧光分析领域最重要的几类探针之一。本文在前人工作的基础上,继续拓展花菁在环境和生物分析方面的应用。本论文共分五章。第一章为绪论,首先综述了花菁的分类、合成方法、各种性质和应用,着重介绍了花菁的聚集性质、以及它在表面活性剂胶束体系和生物体系中的应用研究进展。然后提出了论文设想。第二章研究了花菁I 在表面活性剂溶液中的光谱行为, 并对其作了理论探讨。首先考察了花菁I 在阴离子表面活性剂介质中的吸收光谱特征。花菁I 在近红区770nm 处有一个强的吸收峰。加入一定量的阴离子表面活性剂十二烷基苯磺酸钠(SDBS)能使花菁I 的红区吸收强度降低,根据吸光度的降低值与SDBS 的浓度间呈现的线性关系,我们建立了一种无萃取测定阴离子表面活性剂的分光光度法新方法; 其次,研究了花菁I 在阴离子表面活性剂SDBS 中的荧光性质。实验发现,花菁I 有两个荧光发射峰,分别在短波583nm (激发为265nm,弱荧光)和近红区800nm (激发为765nm,强荧光)。SDBS 的存在可导致花菁I 短波荧光的增强和长波荧光的猝灭。有无SDBS 存在情况下,荧光强度的变化值与SDBS 浓度间均有良好的线性关系。据此,我们分别建立了无萃取直接测定SDBS 含量的新型荧光增强和荧光猝灭方法,并用于环境水样中阴离子表面活性剂的测定。机理研究表明,花菁I 的上述光谱变化源自于花菁在低浓度SDBS 体系中的聚集。与溶剂萃取-分光光度法相比,所建立的三种方法不仅灵敏度高、重现性好,而且分析过程简单、避免了毒性有机溶剂的使用。其中的两种近红区测定方法,还具有光谱干扰少的优势。第三章研究了阳离子花菁II 与核酸的相互作用。实验发现,核酸对花菁II 的荧光具有明显的猝灭作用。针对花菁II 在水溶液中稳定性较差的更多还原

【Abstract】 Cyanine dyes bear the merits of large molar absorbability and high fluorescence quantum yield,and a better sensitivity and selectivity would be obtained if the measurement performed in near-IR region, a region of little interference from background. Furthermore, cyanine is sensitive to environment and its spectra may be varied with the change of microenvironment, which makes it very suitable for many analytical missions. In fact, cyanine has been already become one of the most important probes in fluorescence analysis field. In this thesis, I would continue to develop the application of cyanine in the fields of environmental and biological assays on the basis of previous work of predecessor. The thesis is consists of five chapters. In chapter 1, classifications, various qualities and application of cyanine were firstly summarized. Emphasis was focused on aggregation qualities of cyanines and their recent research progress in the fields of surfactant system and biological system. Then, the research proposal for this thesis is presented. In chapter 2, the spectral behaviors of cyanine I in the presence of surfactants were studied,and the mechanisms of spectral changes were also discussed. Firstly, the absorption changes of cyanine I in anionic surfactants was investigated. The hydrophobic cyanine I showed a moderately strong absorption peak at 700nm. When an amount of anionic surfactant sodium dodecyl benzenesulfonate (SDBS) added, the near-infrared absorption decreased. Moreover, the decreased absorption is proportional to the concentration of SDBS. Based on the absorption changes observed above, a new spectrophotometric method without a procedure of solvent extraction was developed for the determination of SDBS. Secondly, we studied the fluorescence changes of cyanine I in anionic surfactants. Spectra showed that cyanine I has two fluorescence emission maximum at 583nm (with excitation maximum 265nm) and 800nm (with excitation maximum 765nm), respectively. In present of anionic surfactant SDBS, the fluorescence at 583nm enhanced noticeably, while the fluorescence at 800nm quenched dramatically. The extents of fluorescence quenching and enhancing of cyanine I, under optimum conditions, are both proportional to the concentration of SDBS with a good linear relationship according to our observation. Based on the facts, two new fluorescence methods without solvent extraction were developed for the determination of SDBS. Researches show spectra changes of cyanine I are due to the formation of dye premicellar aggregates facilitated by SDBS. Compared with extraction–spectrophotometric method, in addition to high sensitivity and good reproducibility, the three methods for determination of anionic surfactant SDBS significantly simplify the analytical procedure and avoid the toxicity of organic solvent. At the same time, two methods are of low interference due to the measurement performed in the near-infrared region. In chapter 3, the interactions of cationic cyanine II with nucleic acids was studied by means of spectral technique. The fluorescence quenching of cyanine II in the presence of nucleic acids was studied. A near-infrared (NIR) fluorescence quenching method was proposed for the determination of nucleic acids, in which Triton X-100 with proper concentration was employed to improve the stability of this system. The quenching mechanism of fluorescence was also discussed. In chapter 4, the cyanine II-poly-glutamate-proteins ternary ion-association equilibrium system in acidic media was investigated. The cationic cyanine II could not be directly employed to determine proteins due to the lack of evident interaction between cyanine and proteins. However, cyanine II could intensely interact with opposite charged poly-glutamate and form ion-association. Free cationic cyanine II was highly fluorescent in solution, but its fluorescence almost completely quenched in the presence of negatively charged polymers-poly-glutamate. From the absorption blue-shift (from 696 to 628 nm) and fluorescence quenching, we inferred that two d更多还原