Synthesis And Applications Of Novel Nanomaterials

Objective:Due to the excellent optical properties and quantum properties, nanomaterials have been widely used to detect metal ions, organic pollutants, proteins and DNA. Although conventional nanomaterials with high quantum yield, excellent optical properties and high optical stability have been synthesized and developed, toxicity of materials and complex process of synthetic route limit their further applications and development. Therefore, economic, non-toxic and stable nanomaterials obtained through the green synthesis methods are urgently needed. Methods:In this thesis work, through simple and green methods, graphite carbon nitride(g-C3N4), nitrogen doped carbon dots(NCDs) and zeolitic imidazolate framework-8 coated magnetic nanocomposites(Fe3O4@ZIF-8) have been synthesized respectively. Transmission electron microscopy, scanning electron microscope, fourier transmission infrared spectroscopy and other methods were used for the characterization of these nanomaterials. As a fluorescence probe, the fluorescence intensity of g-C3N4 is quenched regularly with the increasement of the concentration of silver ion with an excitation wavelength at 320 nm. With the growth of the concentration of Cu2+, the fluorescence intensity of NCDs decrease regularly. A sensitive probe was developed based on NCD for the detection of Cu2+. In a negative ionization mode, the four nitro-PAHs(1-nitropyrene, 2-nitrofluorene, 6-nitrochrysene, 9-nitroanthracene) were analyzed using MALDI-TOF MS with Fe3O4@ZIF-8 as the matrix. Results:The g-C3N4 were characterized and a sensitive fluorescence probe for determination of Ag+ was developed. The detection limit was 2.73×10-8M with the linear range was 2.0×10-8M-2.0×10-6M. The method has been successfully applied to detect of Ag+ in real water samples with reoveries of 97.4%-103.7%. A novel fiuorescent probe of detecting Cu2+ is structured based on NCDs. The detection limit was 2.07×10-8M with the linear range was 2×10-7M-5×10-6M. The fluorescence probe has been successfully applied to detrecting Cu2+ in real water samples with good recoveries 96.1%-102.0%. Fe3O4@ZIF-8 served as a matrix was succ-essfully applied for the quantitative detection of nitro-PAHs in PM2.5 samples by MAL-DI-TOF MS in negative ionization mode. The limits of detection for 1-nitropyrene, 2-nitrofluorene, 6-nitrochrysene and 9-nitroanthracene were 0.47 ng/μL, 0.92 ng/μL, 4.09 ng/μL and 4.11ng/μL, respectively. The average recoveries of the four nitro-PAHs were ranges from 77.50% to107.38%. Conclusion:A method for detecting Ag+ was presented based on fluorescence quenching of g-C3N4 nanosheets. The quenching process between g-C3N4 nanosheets and Ag+ was mainly static quenching. The impact of the other coexisting cations is almost negligible and the method was successfully used for the determination of Ag+ in real water. A fluorescence probe based on NCDs has been developed for detercting Cu2+. Static quenching is the main quenching mechanism between Cu2+ and the NCDs. The method has been applied to analyze Cu2+ in real water samples with satisfied results. In addition, Fe3O4@ZIF-8 matrix-based MALDI-TOF MS was applied for quantitative analysis of nitro-PAHs in PM2.5 real samples. The good results demonstrate the potential of Fe3O4@ZIF-8 as a matrix in analysis of small molecules by MALDI-TOF MS.