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According to legend, a sense of the application Monolayer Assembly and its water chemical glass surface pyrene

Author: DuHaiYing
Tutor: FangYu
School: Shaanxi Normal University
Course: Physical and chemical
Keywords: Pyrene Fluorescent Films Nitroaromatic Liquid detection
CLC: TP212.2
Type: Master's thesis
Year: 2011
Downloads: 27
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Abstract

Explosives, a wide range of complex, packaging, storage, these factors make it very difficult to accurately detect hidden explosives. Worldwide, commodity explosives the multiple containing nitro aromatic compounds (nitro-aromatic Compounds, NACS). NACs primarily contained trinitrotoluene (2,4,6-TNT), dinitrotoluene (2,4-DNT), picric acid (PA) and other compounds. The NACs is not only prevalent in the commodity explosives, also widely used in the preparation of pharmaceuticals, pesticides, dyes, etc.. NACs toxic and difficult to degrade, it is a serious environmental pollutants. Therefore, the solution in the rapid and sensitive detection of explosives for anti-terrorism, counter-terrorism, and environmental quality monitoring and so has a very important significance, deserves special attention. So far, it has been developed from the the solution electrochemical method, high performance liquid chromatography, gas chromatography - mass usage of surface-enhanced Raman method, fluorescence method, including a variety of explosives detection method. In these methods, fluorescence method, high sensitivity can be rich in acquisition parameters, the instrument is simple and concern. The first chapter of this thesis, a the homogeneous fluorescence sensor for liquid explosives detection, Fluorescent Film Sensors particle fluorescence sensors and biological fluorescence sensor. A brief review of the advantages and disadvantages of the various methods, pointed out that the chemical film-based fluorescent sensors for its good stability, can be used repeatedly and likely to become a hot liquid explosives detection methods research. More than ten years, the research team has been committed by the self-assembled monolayer (Self-assembled Monolayers, SAMs) technology designed and fabricated a variety of highly sensitive, highly selective fluorescent sensing film. Based on the specific interaction of weak polarity connection arm layer shielding effect \sensing films. The study found that the connecting arm of the structure, polarity, flexible film sensor has an important impact on performance. Further, the present laboratory was found in the course of the study of the small organic molecules of the gelling agent, will produce a significant effect for the self-assembly of the gelling agent in solution in a simple benzene ring is introduced in between the two cholesterol unit. Based on the above consideration and this laboratory research work, this thesis SAMs technology pyrene fluorescent species as a sensing element, the glass matrix, an attempt to the benzene ring is introduced into the connecting arm, to prepare the corresponding pyrene chemical modification fluorescent film . The research found that such a film rich photophysical behavior in solution can be used for liquid NACs highly sensitive, highly selective detection. The first part of the research work based on the glass matrix, pyrene as the sensing element, introduction of the polarity of the urea group and a benzene ring unit in the connecting arm, using SAMs prepared adjustable microenvironment of a surface can be used for aqueous phase nitrated the base aromatic compounds detected pyrene functional fluorescent film. The difference compared with existing relatively hydrophobic alkyl chains mediated pyrene functional film, the film in that the connecting arm are introduced in the polarity of the connecting arm (ureido), so that the hydrophilicity of the entire connecting arm greatly increase microenvironment film is more sensitive to contribute to the in-depth understanding of the model of \Pyrene introduction of the benzene ring in the connecting arm, so that the surface of the film not only a perfect excimer (Excimer) peak emission, but distorted Excimer peak emission. Pyrene electron-deficient NACs electron transfer between the role of a sensitive and selective detection of the liquid phase NACs. The second part of the research work, the same is glass matrix pyrene as a sensing element, secondary amino groups and the benzene ring unit introduced in connection arm, using SAMs prepared by a sub-structure of the connecting arm but also containing benzene ring unit The fluorescent sensing film, in order to further investigate the introduction of benzene rings in the connecting arm on the performance of the thin film sensor solution phase NACs. The results show that the introduction of the benzene ring in the connecting arm helps to π-π stacking of the connecting arm, so that the end of the pyrene more easily exposed in the water phase, thus the rapid detection of the aqueous phase of the NACs. This film is the detection limit of picric acid reached 1.0 × 10-8 mol / L. Found that the excellent reversibility of this thin film sensor, benzene, toluene, chloroform, ethanol, NaOHoHCl, and seawater, etc. of the film fluorescence emission and picric detect almost no effect. The fluorescence lifetime measurement proved NACs film fluorescence quenching in essence are static quenching.

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