Novel Fluorescence Sensors Based On Covalent Immobilization Of Fluorescent Carrier

In this thesis, several new fluorescence carriers have been synthesized bearing a carbon chain with a terminal double bond introduced into the molecule and copolymerized with a monomer under UV irradiation on the silanized glass or quartz disk. The sensors prepared were studied. Covalent immobilization effectively prevents the leakage of the carrier dye from the sensor membrane, a phenomenon that shortens the lifetime of ordinary optical sensors. These sensor prepared have been applied to analysis of different species.(1) Carbazole is a promising pharmaceutical species. A novel optical sensor for determining doxycycline based on the fluorescence quenching of N-allylcarbazole immobilized on an quartz glass plate surface by covalent bonding has been described. The sensor shows satisfactory virtues in reversibility, repeatability, selectivity and sufficient lifetime resulting from its excellent optode membrane. Its response time is less than 60 seconds. The determination range and detection limit of the sensor are 6.0+10-7 2.0+10-3 mol.1-1 and 2.0+10-7 mol.1-1, respectively. The lifetime of each sensor is at least three to four months. The sensor can be used for direct determination of doxycycline in pharmaceutical preparations and urine samples.(2) An aminobenthiazole schiff base has been synthesized as a new fluorescence carrier by reacting 2-aminobenthiazole with p-allyoxybenzoldohyde. The new kind of schiff base can be utilized for preparing an optical sensor, used for determining furazolidone based on the fluorescence quenching. Aminobenthiazole schiff base immobilized on a glass plate surface by covalent bonding can circumvent the leakage of the fluorephore from the sensor surface and guarantee a relatively long working lifetime. The sensor shows satisfactory virtues in reversibility, repeatability, selectivity and sufficient lifetime. Its response time is less than one minute. The determination range and detection limit of the sensor are 1.0+10-6-1.0+10-3mol.1-1 and 6.0+10-7 mol.1-1. respectively. The sensor can be used for direct determination offurazolidone in pharmaceutical preparations and urine samples.(3) Another schiff base was synthesized by reacting 2-aminobenzanthrone with p-allyoxybenzoldohyde and used for determination of iodine based on fluorescence quenching. As a fluorescence carrier, the aminobenzanthrone schiff base was immobilized on a glass plate surface by covalent bonding. The sensor possesses a short response time, nice reproducibility and reversibility. Iodine in solution can be determined in range between 1.0+10-5 and 1.0+10-3 mol.1-1. The determination limit of the sensor is 6.0+10-6 rnol.l-1'. The sensor has been applied to the dettermination in sodium chloride.(4) 4-methyl-7-allyloxynaphtho[l, 2-b]pyran-2-ketone has been synthesized as a fluorescent carrier for preparing optical chemical sensor and used for direct determination of nitrofurazone. The carrier is immobilized on a quartz glass plate surface treated with a silanizing agent to prevent the leakage of the dye. This sensor can be utilized for nitrofurazone assay based on fluorescence quenching. The sensor shows good repeatability, long lifetime and a fast response of less then 2.5 min. Nitrofurazone can be determined in the range between 6.0+10-6 to 8.0+10-4mol.1-1' with a detection limit of 4.5+10-6 mol.1-1 at pH 6.0.