Preparation And Application Of Fluorescence Chemical Sensor Based On Water-Soluble Conjugated Polymer PPE-OBS

Water-soluble conjugated polymers are a class of linear polymer that have a main chain with the larger conjugated ?-?* electronic structure and side chain modified hydrophilic groups.It not only has higher emission quantum yield,better chemical structure stability,fluorescence amplification and superquenching property,but also has good water solubility and strong electrostatic effect.According to these merits,water-soluble conjugated polymers have been widely used in fluorescent biochemical sensors for the detection of metal ions,biomolecules and organic small molecules.In my research work,the carboxyl-modified water-soluble conjugated polymer,poly(2,5-bis?sodium 4-oxybutyrate?-1,4-phenylethynylene-1,4-phenyleneethynylene,PPE-OBS,was synthesized and the detection of metal ion and cysteine-containing compounds using PPE-OBS was studied.In the first chapter,we summarized conjugated polymers including their classification and the application progress of water-soluble conjugated polymers in the fields of metal ions,biomolecules and organic small molecules.In the second chapter,we introduced the detailed synthesis route of the water-soluble conjugated polymer PPE-OBS.Structures of intermediates and target products were characterized by nuclear magnetic resonance?NMR?,mass spectrometer?MS?,infrared spectrometer?IR?,thermogravimetric analysis?TGA?and gel permeation chromatography?GPC?.In the third chapter,a Hg²⁺ fluorescent sensor based on water-soluble PPE-OBS was developed.Meanwhile,the experimental conditions for the test were optimized.The sensing mechanism of the Hg²⁺ sensor was studied by means of a fluorescence microscope.Under the best experimental conditions,the results showed that the linear range of Hg²⁺ is 6×10-8⁸×10-5 mol L-1,and the detection limit is as low as 2.10×10-9 mol L-1.Finally,the sensor was applied to Hg²⁺ detection in environmental water samples.In the fourth chapter,a fluorescence sensor was developed to detect cysteine-containing compounds based on PPE-OBS-Hg²⁺ system.In the optimal experimental conditions,the sensor has a better linear relationship,higher sensitivity and higher selectivity contrast with other sensors.The detection limits for cysteine?Cys?,homocysteine?Hcy?and reduced glutathione?GSH?were 0.725 ?mol L-1,0.982 ?mol L-1 and 1.21 ?mol L-1,respectively.Finally,the senser was used for the detection of cysteine in green tea beverages and honey samples.The experimental result is satisfied.It shows that this method has a certain practicality and reliability in the detection of cysteine in actual sample.