| Optical chemical biosensing is a technique applied to selectively express real-time information of chemical and biological components with optical signal in detection system. It is used more and more widely in many important application fields such as life sciences, environment monitoring, illnesss diagnosis, medication screening, food industrial and material sciences.The droplet optical chemical biosensor has the function of continuous producing fresh reagents and reacting with fresh samples. The infection of optical signal, which caused by the absorption and scattering of cell surface or the contaminations of reagents and samples to cells in conventional photometric analysis, can be avoided. The unique features of a liquid drop can be characterized in its reproducibility, renewability, defined volume, and lack of containment walls. The features individually or in combination, may result in high sensitivity and accuracy for analytes.Vitamin is a kind of important micronutrients and has a close relationship with the human health. It is significant to determine the content of vitamins in pharmaceutical preparations or in foods. A novel flow injection drops spectrofluorimetry, combining with drop-based optical chemical sensor with flow injection technique, has been established to fast detect water-soluble vitamins such as folic acid, ascorbic acid and complex-vitamin B in pharmaceutical preparations. This method is automatic, short time, low reagent cost and real-time in determination of vitamins in medication manufacture.The contents of this thesis include as following:1. A fluorometry based on optical chemical sensor combined with flow injection technique has been developed for the determination of folic acid. The method is based on the chemical property of folic acid with weakly native fluorescence oxidized by potassium periodate to form fluorescent product in acidic medium. Under optimumconditions, the calibration graph was obtained over the range of 0.02~2.84/ug/mLfor folic acid with the limit of detection of 0.001 //g/mL. The sensor was applied to assay folic acid in pharmaceutical preparations with satisfactory results.2. Ascorbic acid was converted to dehydroascorbic acid with the oxidation of mercury (II) ion and then condensed with o-phenylenediamine producing fluorescent quinoline. Based on this derivatization reaction, the content of ascorbic acid in vitamin C tablet was determined utilizing droplet optical chemical biosensor. Under optimum conditions, the sensor shows linear response in the range from 0.06 ~ 13.2 fig/mhfoT ascorbic acid. The regression equation is F - 77.78+51.39C.3. A novel optical chemical sensor based on the liquid drops combined with flow injection-solid phase has been developed for continuous and sequential determinations of the mixture of vitamin Bi (VBi), vitamin B2 (VB2) and vitamin B6 (VB6). Quantitative determinations of VBi, VBo and VB6 were carried out based on selective adsorption of Sephadex CMC-25 and different fluorescence characteristics of VBi, VB6 in the basic solutions. This method has been applied in the determination of synthetic mixture of VBi, VB2, VB6 and vitamin B compound tablets with satisfactory results. Under optimum conditions, linear calibration curves were obtained over the range of 0.01-8.00 jug/m\, 0.01-10.00 /ig/ml and 0.01-3.00 ^g/ml for VBX, VB2 and VB6 with the limits of determination of 0.008, 0.005 and 0.006/fg/ml, respectively. The method is fast in assay and low in reagent cost. The errors results from optical instability of VB2 and VB6 in previous analysis and overlap of fluorescence peak are eliminated.
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