Preparation And Application Of Highly Selective Adsorbent For Tetracycline Antibiotics Residues In Food

The problem of tetracycline residues in animal food caused by antibiotic abuse is one of the food safety problems.Because the matrix of food sample is more complex,the sample pretreatment process needs to be carried out before the instrument analysis is carried out.In this thesis,in order to shorten the sample pretreatment process,two kinds of tetracycline molecularly imprinted polymers were prepared by surface molecular imprinting and Pickering emulsion method,which were used as adsorbents for solid phase extraction and combined with high performance liquid chromatography?HPLC?for the detection of tetracycline in fish,chicken and milk.Its main contents are as follows.?1?A novel hydrophilic tetracycline-imprinted foam polymer with excellent selectivity and porosity was synthesized with a three-dimensional carbon composite of graphene oxide and carbon nanotube by freeze-drying.The synthesized materials with super selectivity,which could distinguish high similar structural analogues of tetracycline and oxytetracycline,and the maximum adsorption capacity for TC?MW:444.44,19.31 mg/g?was 2-fold greater than its structural analogue of OTC?MW:460.43,6.48 mg/g?.The synthesized materials were characterized by Fourier transform infrared spectrometry,scanning electron microscopy,nitrogen sorption and thermogravimetry analysis.The adsorption mechanism and adsorption performance of the synthesized materials were detailed studied through the adsorption isotherms,adsorption kinetics,competitive adsorption and selective adsorption experiments.Further,a method was established by using TC-imprinted foam polymers as the adsorbent of solid phase extraction that coupled to liquid chromatography for the detection of TCs residues in food samples.Under the optimum conditions,the method detection limit was 1.27?g/kg.Three samples?milk,chicken and fish?spiked with tetracycline at three levels were determined according to this method,the results showed good recoveries and RSD ranging from 85.58%to 116.87%and 0.19%to8.92%?S/N=3?,respectively.?2?SiO₂ particles were used as stabilizers to establish a stable Pickering oil–water emulsion,and then the molecularly imprinted polymers were fabricated by polymerization in the presence of functional and cross-linked monomers in the oil phase.The synthesized materials with super selectivity,which could distinguish high similar structural analogues of tetracycline and oxytetracycline.The synthesized materials were characterized by Fourier transform infrared spectrometry,scanning electron microscopy and thermogravimetry analysis.A series of static adsorption experiments were conducted to analyze their adsorption performance for TC,such as adsorption isotherms,adsorption kinetics,competitive adsorption and selective adsorption experiments.Further,a method was established by using TC-imprinted polymers as the adsorbent of solid phase extraction that coupled to high performance liquid chromatography for the detection of TCs residues in food samples.Under the optimum conditions,the method detection limit was 1.84?g/kg.Four samples?milk,chicken,fish and water?spiked with tetracycline at three levels were determined according to this method,the results showed good recoveries and RSD ranging from74.89%to 114.74%,and 0.35%to 9.81%?S/N=3?,respectively.