Novel Fluorescence Sensors Based On Covalent Immobilization Under UV Radiation Of Fluorescent Carrier

This thesis is mainly centered on the following two research aspects: 1) Several new fluorescence carriers have been designed and synthesized bearing a carbon chain with a terminal double bond introduced into the molecule and copolymerized with a monomer under UV radiation on the silanized glass or quartz disk. The sensors prepared were studied. These sensors prepared have been applied to analysis of different species. 2) Some sensors were prepared and applied through PVC embedded several new fluorescence carriers synthesized. Details are presented in this thesis as follows:1. A novel optical sensor for determining nitrofurazone has been proposed based on the fluorescence quenching of 4-methyl-8-methylacrylamide-2H, 5H-pyrano [3, 2-C] benzpyran 2, 5-dione (MMPBD) immobilized on an quartz glass plate surface by covalent bonding. The sensor shows satisfactory virtues in reversibility, repeatability, selectivity and sufficient lifetime resulting from its excellent optode membrane. Its response time is less than 50 seconds.2. In order to extend the scope of possible analytes for the group of coumarin derivatives, it is thought that an effecient approach is to retain the amino group of 4-hydroxy-7-aminocoumarin (HACM) as the reacting site for analyte and modify the hydroxy group at 4-position of the same compound to introduce a terminal double bond capable of being covalently grafted on the sensor surface. In this paper, HACM is reacted with bromopropylene to form 4-allyloxy-7-aminocoumarin (AAC). The later compound is copolymerized on a modified quartz glass surface. The sensing membrane prepared in this way shows strong fluorescence which can be quenched by some chemical compounds such as indole-3-acetic acid (IAA). The quenching effect can be utilized for fluorimetric determination of IAA. Compared with conventional methods, this sensor has lower cost, wider detection range, higher sensitivity and selectivity, better reproducibility and reversibility.3. From carbazole, authors synthesized 9-aminocarbazole. Taking advantage of excellent fluorescence properties of 9-aminocarbazole, we introduced into 9-aminocarbazole a terminal double bond capable to copolymerize with a monomer on the sensor surface. Reacting 9-aminocarbazole with methylacryloyl chloride to form 9- methylacryloylamino carbazole (MAC) could realize the introduction of terminal double bond. MAC has been utilized to prepare a fluorescent sensor and used for the determination of NO2 for environment at monitoring. The sensorshows sufficient repeatability, selectivity, operational lifetime of 8 weeks and a fast response of less then 30 s. The sensor can be used for direct determination of NO2 in pond water samples and the results were in agreement with those of a standard method.4. The carbazole derivative, 9- ethyl-3-carbazylidene carbazole hydrazone (ECCH) with conjugated two carbazole ring has been applied as a fluorescence carrier for preparation of an iodine sensitive optical chemical sensor. Most commonly coexisting ions do not interfer with the iodine assay. The sensor shows sufficient repeatability, selectivity, an operational lifetime of one month and a fast response of less then 50 s.5. An optical chemical sensor based on a fluorescent dye l-allyloxy-4-hydroxyanthracene-9, 10-dione (AHD) having terminal double bonds, which are covalently bond to quartz glass plate surface treated with a silanizing agent to prevent its leakage. This sensor was used to measure water content in the organic solvents such as acetone. The sensor is resistant to swelling, the membrane possesses relatively long lifetime and short response and recovering time.6. The preparation of a fluorescence pH sensing membrane based on immobilization of two dyes (1-allyloxy- 4- hydroxyanthrance-9, 10-dione and 5 -(4 - amidophenyl)-10, 15, 20- triphenylporphrine) with close excitation peaks is described. The sensing membrane has a useful pH range covering 2.0 to 13.5. The feasibility of using the proposed pH assay method has been tested by using PL...