Preparation And Characterication Of Molecularly Imprinted Nanoparticles And The Absorption Characteristic To Fluoroquinolones

In recent years, antibiotic residue in environments has gained increasing concern all over the world. Fluoroquinolone compounds (FQs) are a group of synthetic antibiotics, which are widely used in human, veterinary medicines, and aquatic breeding. Due to incomplete utilization in body, most of FQs are finally released in their original forms or metabolites into water and soil environments, resulting in great potential threat to ecological environment and human health. The aim of this thesis is to develop a type of novel sorbent for remove of FQs residue in water environment. The main contents include:In the first section, uniform mesoporous silica nanoparticles (MSNs) were synthesized by the modified Stober method, using tetraethoxysilane (TEOS) as precursors and cetyl trimethyl ammonium bromide (CTAB) as surfactant. Further, uniform mesoporous carbon nanoparticles (MCNs) were prepared using MSNs as solid template, glucose as carbon source under N2atmosphere. The prepared MCNs were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), and N2adsorption-desorption experiments. Results showed that the MCNs have a uniform size of200nm, high surface area (980m2g-1), and narrow pore size distribution (1.9nm).In the second section, molecularly imprinted polymer was prepared on the surface of MCNs by precipitation polymerization at60℃using ofloxacin as template, trimethylolpropane (TRIM) as crosslinker, acrylamide (AM) and methacrylic acid (MAA) as functional monomers, acetonitrile as solvent, and AIBN as initiator. The achieving molecularly imprinted polymer coated MCNs nanoparticles (MCN-MIP) were characterized by FTIR, SEM, and thermogravimetric analysis. Results showed that MCN-MIP with a uniform size of200nm were succssfully prepared using MAA as functional monomer and60mg MCNs. Absorption properities of MCN-MIP were studied by a series of absorption experiments using ofloxacin water solution as model sample.The absorption reached an equilibrium, with the largest adsorption capacity of40.2mg/g. The adsorption behavior fitted Langmuir adsorption isotherm and pseudo-second-order kinetics model.Effect of pH, ionic strength, and washing solvent on the absorption was studied. MCN-MIP achieved the best absorption performance for ofloxacin at pH7.0, no salts addition. And a washing procedure following the absorption could greatly improve the selectivity to the target molecules. Finally, MCN-MIP were used to absorb six FQs in sea water, the removing efficiency was more than90%, with relative standard deviations (RSDs) of3.69-6.57%. In additional, MCN-MIP were used to selectively extracte FQs in spiked milk sample, with recoveries of74.2-101.2%. The prepared MCN-MIP have great potential applications in highly efficient and selctive remove and extraction of FQs in complex samples.