Study On The Perparation And Application Of Carbon Quantum Dots And Spectroscopy Analysis Of Fluoroquinolones

In recent years, as a new fluorescent carbon nanomaterials carbon quantum dots have attracted a lot of attentions, because they have high fluorescence intensity, good light stability, anti-photobleaching, low toxicity and excellent biocompatibility. By introducing the background and development of fluorescent carbon quantum dots, this thesis explores the fluorescent CQDs as a fluorescent probe for efficient selective folic acid., and we explore the synthesis of CQDs using one-step hydrothermal method, which use perfluorooctanoic sulfonate as the carbon sources and their applied for detection of Fe3+ ions. We also study on the spectrum property of fluoroquinolone based on upconversion photoluminescence property.(1) In NaH2PO4-Na2HPO4 buffer medium (pH 7.3), the electrostatic interaction of folic acid with carbon quantum dots results in the fluorescence quenching of carbon quantum dots characterized at 384nm. Experiments show that the quenched fluorescence intensity is in proportional to the concentration of folic acid content over the range of 0.025-2.0 μmol/L with a correlation coefficient of 0.9947. Therefore, a sensitive fluorescence spectrophotometry method for the determination of folic acid was developed. The limit of detection (LOD) is 2.5 nmol/L. In this work, the fluorescence spectra, UV-Vis spectra and fluorescence lifetime were characterized. The reaction mechanism and the optimum of reaction condition were also investigated. Finally, this method has been applied for the determination of folic acid in simulated serum with the recovery from 97.3% to 101.6% and the RSD lower than 4.85%.(2) One-step hydrothermal synthesis of fluorescence carbon quantum dots used perfluorooctanoic sulfonate as carbon source and peroxide as passivant. Study their optical properties, particle size, fluorescence quantum yields and particle size of carbon quantum dots. It is found that the carbon quantum dots have good water solubility, light stability and biocompatibility. Through different instruments ware measure the functional groups, the carbon quantum dots contain a lot of hydroxyl groups and carbonyl containing group. Finally, the experiment shows that carbon quantum dots can be sensitive to Fe3+, and it will be applied to the detection of Fe3+.(3) The upconversion photoluminescence property of fluoroquinolones has been discussed. Based on the principle of upconversion photoluminescence, a simple strategy has been developed for detection of fluoroquinolones. And the reaction of acidity, temperature, solvent and stability were also investigated. The upconversion photoluminescence intensity of the system showed a good linear relationship with the concentration of ciprofloxacin over the range of 0.05-20 μmol/L with a correlation coefficient of 0.9935 and for levofloxacin over the range of 0.05-30 μmol/L with a correlation coefficient of 0.9976. The limit of detection (LOD) was determined is 5.0 nmol/L for ciprofloxacin and 5.0 nmol/L for levofloxacin. This method was also applied to the analysis of human serum or pharmacy sample the recovery of ciprofloxacin and levofloxacin ranged from 99.0% to 102.7% and the RSD lower than 2.62%.