Synthesis And Application In Food Detection Of Mixed-templates Molecularly Imprinted Polymers For Fluoroquinolones

This thesis consists of three chapters.IN CHAPTER ONE, the development history and basic principle of the molecularly imprinting technology (MIT) were described. The preparation methods of molecular imprinting polymer (MIP) and the application of MIP in food detection were also reviewed.IN CHAPTER TWO, a high-performance liquid chromatography-diode array detection method (HPLC-DAD) for the determination of fluoroquinolone antibiotics in milk has been developed using molecularly imprinted polymer solid phase extraction (MISPE). The molecularly imprinted polymer (MIP) has been prepared using levofloxacin and ciprofloxacin as the templates,α-methacrylic acid (MAA) as functional monomers and trimethylolpropane trimethylacrylate (TRIM) as crosslinker. The imprinted polymer has been characterized by equilibrium binding experiment to investigate the binding ability to template molecule. Various parameters affecting the extraction efficiency of the polymer in the MISPE procedure have been evaluated to achieve optimal preconcentration followed by a elution with 4% ammonia in methanol. The resides are extracted from milk with 2% acetic acid in acetonitrile, purified on the MISPE cartridge and then analyzed using HPLC-DAD set at 281 nm. The method has been validated by analyzing spiked milk samples at two levels (100 and 200μg·kg-1 ), the mean recoveries of the method range from 84.1 to 104.7% with relative standard deviation no more than 4.3% (n=3) for fleroxacin, enoxacin, pefloxacin, norfloxacin, ciprofloxacin, levofloxacin, lomefloxacin, enrofloxacin, gatifloxacin, sparfloxacin, the method detection limits range between 1.34 and 7.35μg·kg-1. The HPLC-DAD validated method was proved to be suitable for the sensitive and accurate quantification and confirmation analysis for the residues of fluoroquinolones.IN CHAPTER THREE, a method has been established for simultaneous determination of residues of ten fluoroquinolones in grass carp by high performance liquid chromatography-ion trap mass spectrometry (HPLC-ITMS). The samples were extracted with 2% acetic acid in acetonitrile and defatted with n-hexane, then purified by the self-made molecularly imprinted cartridge. The preparation of samples and the separation conditions had been optimized, HPLC was performed with a gradient elution program while acetonitrile and water (containing 0.05% formic acid) were used as mobile phase. The identification and quantification were done with ion trap mass spectrometry. The recoveries ranged from 80.6 to 104.6% while the relative standard deviations below 8.6% (n=3). The limits of detection (LOD) were 0.11-0.25μg·kg-1 and the limits of quantification (LOQ) were 0.35-0.84μg·kg-1. This method is suitable for validation and multi-residue analysis of fluoroquolones in aquatic products.