The Novel Immobilization Methods Of Indicators And Their Applications In Preparation Of Fluorescence Sensors

There has been considerable interest in studying fluorescence sensors because they can be applied to a wide range of analytical tasks, such as clinical diagnosis, bioassay, environmental monitoring, etc. In the design and fabrication of fluorescence sensors or probes, immobilizing indicators is a crucial step. The immobilization methods play an important role in the property of the obtained sensors or probes. Aiming at the problems existed in present fluorescence sensors or probes such as dye leaching, photobleaching, this research developed several new strategies of immobilizing indicators in order to improve the ability to resist photobleaching, prevent dye leakage and shorten response time. The obtained sensors or probes were used to determine some medicines, picric acid and primary amines. The detail contents are as follows:1. A general route for preparation of dye-encapsulated polymer particles via a microemulsion polymerization process has been described. 1-Naphthaleneboronic acid (NBA) was embedded as an example. The obtained NBA-encapsulated polymer particles were used as a fluorescence probe for cilnidipine assay. This probe showed a linear response toward cilnidipine over the concentration range of 2.0×10?7 mol l-1 to 1.1×10?5 mol l-1 with fast respone time. Its sensitivity to cilnidipine was largely improved in comparison with that of free NBA. The ability of the NBA in the probe to resist photobleaching is stronger than free NBA due to the protective effect of the polymer film on the entrapped dye.2. A novel method of immobilizing indicators by combining microemulsion polymerization with covalent bonding was developed. A terminal double bond was attached to 3-amino-9-ethylcarbazole (AEC) via methacryloyl chloride. The resulting compound, 3-(N- methacryloyl)amino-9-ethylcarbazole (MAEC), was copolymerized with butyl methacrylate by microemulsion polymerization. The MAEC-immobilized polymer particles were obtained and used as a fluorescence probe. This probe shows almost free of dye leaching, higher photostability in comparison with free AEC. In present study, the proposed probe was used to assay metronidazole. Results show that the probe has a linear response to metronidazole in the range from 2.0×10?5 mol l-1 to 1.0×10?3 mol l-1 with a detection limit of 9.0×10?6 mol l-1.3. A fluorescence indicator, 1-amino-4-allyloxyanthraquinone (AAA), with a...