Preparation And Application Of Highly Selective Adsorption Materials For Tetracyclines Trace Residue In Animal Derived Foods

Tetracycline antibiotics are widely used in animal breeding because of their broad spectrum antibacterial properties.However,these drugs are often abused,resulting in a large number of residues in animals,which have the potential risk of damaging teeth,bones,digestive tract,liver and kidney,and even seriously endangering the safety of human life after human consumption.Therefore,it is important to establish a convenient and effective method for the detection of tetracycline antibiotics in animal-derived foods.Molecularly imprinted polymers are highly selective because they contain pores that complement each other in shape,size and interaction sites with template molecules.The magnetic molecularly imprinted polymer combines the magnetic medium with the molecularly imprinted polymer and can be separated from the substrate without centrifugation or filtration under the action of an external magnetic field.Magnetic molecularly imprinted polymers were prepared by two methods.The polymers were used as solid phase adsorbents for the determination of trace tetracycline residues in practical samples by liquid chromatography.The main contents and results are as follows:A magnetic molecularly imprinted polymer with high selectivity for tetracycline antibiotics was synthesized by bulk polymerization,using tetracycline hydrochloride as a template molecule,methacrylic acid as a functional monomer,ethylene glycol dimethacrylate as a crosslinker,azobisisobutyronitrile as initiator and Fe₃O₄@SiO₂ as a magnetic carrier.The structure of magnetic molecularly imprinted polymer was characterized by Fourier transform infrared spectroscopy,scanning electron microscope and thermogravimetric analysis.The adsorption properties of magnetic molecularly imprinted polymers were characterized by adsorption kinetic experiments,equilibrium binding experiments and selective experiments.And this polymer is used as solid phase adsorption.The minimum detection limits of the three tetracycline antibiotics were 1.53μg/L,1.13μg/L,and 1.33μg/L,respectively.The spiked levels of 3 levels（50μg/kg,100μg/kg,200μg/kg）were tested on chicken,fish,and milk samples.The recoveries for chicken,fish,and milk were 75.85%⁹0.73%,78.08%⁸4.35%,and 76.74%⁹2.16%,respectively,and the RSDs were 1.8%⁶.7%,1.2%⁷.3%,and 2.2%⁵.9%,respectively.The preparation conditions of this method are easy to control and the amount of solvent consumed is less,which can avoid the interference of other substances to the detection.The magnetic molecularly imprinted polymer for tetracycline antibiotics was synthesized by reflux precipitation polymerization in the presence of functional monomers,crosslinker,and initiator,with oleic acid modified Fe₃O₄ as magnetic carrier.The structure of magnetic molecularly imprinted polymer was characterized by Fourier transform infrared spectroscopy,scanning electron microscope and thermogravimetric analysis.The adsorption properties of magnetic molecularly imprinted polymers were characterized by adsorption kinetic experiments,equilibrium binding experiments and selective experiments.Under the optimal extraction conditions,the minimum detection limits of the three tetracycline antibiotics were 2.42μg/L,2.85μg/L,and 1.38μg/L,respectively.The spiked levels of 3 levels（50μg/kg,100μg/kg,200μg/kg）were tested on chicken,fish,and milk samples.The recoveries for chicken,fish,and milk were 76.75%⁹1.08%,77.58%⁹1.20%,and 79.09%⁹2.42%,respectively,and the RSDs were1.46%⁹.64%,0.97%⁵.08%,1.59%⁴.58%,respectively.The method shortens the preparation time,improves the efficiency,and has good sensitivity and recovery.