Preparation And Analytical Application Of Functionalized Magnetic @ Fluorescent Nanocomposites

Due to high sensitivity, good selectivity, simple manipulation, and good reproducibility. Fluoremery has attracted more and more attention in different research areas, such as, biochemistry, physics, industry and chemistry. However, the number of molecules with fluorescent properties is very small, which restricts the application of direct fluoremetry. Therefore, it is very important to design and synthesize fluorescent reagents with good fluorescent properties, and thereby to establish sensitive to extend the application of fluoremetry in various scientific disciplines.Magnetic nanoparticles possess some distinguished characteristics, such as, high specific surface area and easy to separate. In addition, they can be endowed with different functional groups, such as, -COOH, -OH, -CHO, -ArCH₂Cl, -NH₂ and so on, on surface by coplolymerization or surface chemical modification,In this thesis, Fe₃O₄ magnetic nanoparticles as a functional core and fluorescence materials as a shell was chosen to prepare magnetic and luminescent nanocomposites, and thereby use them as fluorescent probes to determine proteins and heavy metal ion. The details are sumarried as follows: (1)Fe₃O₄/(NaOL/CTAB)_n/PABA nanocomposites were prepared by taking advantage of layer-by-layer technique. Then a novel fluorescence method was proposed for the determination of proteins based on the enhancement effect of proteins on the fluorescence of Fe₃O₄/(NaOL/CTAB)_n/PABA nanocomposites. Under optimal conditions, the linear ranges of calibration curves were 0.2-20μg mL^-1, 0.2-13μg mL^-1, 0.2-10μg mL^-1 forγ-globulin (γ-IgG), human serum albumin (HSA), and bovine serum albumin (BSA), respectively. The detection limits were 0.02μg mL^-1, 0.01μg mL^-1, 0.02μg mL^-1 forγ-IgG, HSA and BSA, respectively.(2) Magnetic and luminescent nanocomposites Fe₃O₄/Py/PAM was prepared by adsorption under ultrasonic irradiation. The reaction between the functional composite nanomaterials was observed and Cr (VI) by Fluorescence spectrum, and then a sensitive FL method for the determination of Cr (VI) was established.(3) Y₂O₃:Ln³⁺ (Ln³⁺=Eu³⁺, Tb³⁺, Yb/Er³⁺) nanocrystals were prepared by solvent method. They are characterized by TEM images, XRD and Fluorescence spectra. The fluorescence properties in different polarity solvent were also investigated.