Preparation Of Two Hydrophilic Ionic Liquid Imprinted Materials And Their Specific Recognition Of Macrolide Antibiotics

With the widely use of macrolide antibiotics,their drug residues and environmental exposure pose a huge potential threat to human and ecosystem.To ensure the healthy development of human and ecosystem,macrolide antibiotics in environmental media must be effectively monitored.However,macrolide antibiotics in actual samples with the low concentration are interfered by complex environmental matrix.So,efficient purification and concentration pretreatments are essential procedures for effective monitoring.Based on the specific recognition of molecular imprinting technology,combined with solid phase extraction technology,it can achieve high-efficiency selective separation and enrichment of low-concentration targets under complex matrix interference,thus improving the accuracy and sensitivity of detection.The ionic liquids called"green solvent"have unique chemical structure,which are easyly to generate hydrogen bonds,static electricity,π-πand other interactions with target molecules,and have a structurally designable outstanding advantage.With the ionic liquids as functional monomers,the preparations and applications of the molecularly imprinted polymers in aqueous phase can be realized,thereby overcoming the defects of high toxicity of preparation solvents and water incompatibility of conventional imprinted polymers.In this work,ionic liquids of 1,4-butyl-3,3’-di-1-vinylimidazolium chloride（[BIM-4C]Cl）and1-allyl-3-vinylimidazolium chloride（[VAIM]Cl）were respectively combined with the aqueous monomer2-acrylamide-2-methylpropane sulfonic acid（AMPS）as bifunctional monomers to prepare tylosin tartrate and kitasamycin tartrate surface imprinted polymers in pure water solvent by surface molecular imprinting technique.The chemical structure,apparent morphology,microstructure and thermal stability of imprinted materials were characterized by various means.The adsorption properties and characteristics of two imprinted materials were studied by equilibrium adsorption experiment.Combined with high performance liquid chromatography,the practical application values of two self-made molecularly imprinted solid phase extraction columns were studied respectively with three kinds of animal food samples（pork,chicken,beef）as analysis objects.The results are shown as follows:1.Reviewing the characteristic,current status,hazards,commonly detection methods and commonly pretreatment methods of macrolide antibiotics;Expounding the principles,classifications and synthesis methods of molecular imprinting techniques;Disserting the characteristics and advantages of ionic liquids and their application in molecular imprinting techniques.2.1,4-butyl-3,3’-di-1-vinylimidazolium chloride（[BIM-4C]Cl）and 1-allyl-3-vinylimidazolium chloride（[VAIM]Cl）respectively combined with 2-acrylamide-2-methylpropane sulfonic acid（AMPS）as bifunctional monomers,two surface molecularly imprinted polymers of tylosin tartrate and kitasamycin tartrate were prepared in pure aqueous medium.Combined with equilibrium adsorption experiments,the preparation conditions of two kinds of polymers were optimized by control variate method,respectively.The interactions between the templates and the monomers were studied by ultraviolet absorption spectroscopy.The chemical structure,apparent morphology and thermal stability of two kinds of polymers were studied by characterization methods of infrared spectroscopy,field emission scanning electron microscopy,specific surface area measurement,and comprehensive thermal analysis.3.The adsorption characteristics of tylosin tartrate(MIP_TYL)and kitasamycin tartrate(MIP_KITA)surface imprinted polymers were studied by equilibrium adsorption experiments.The results showed that:（1）within the experimental range,the adsorption of the tylosin tartrate surface molecularly imprinted polymers for the template was spontaneously endothermic behavior.The adsorption process conformed to the Freundlich isotherm adsorption model and the pseudo-first-order adsorption kinetics model.Selective adsorption experiments showed that MIP_TYL has strong class-specific recognition ability for template molecule TYL and its structural analogs tilmicosin phosphate（TIL）and kitasamycin tartrate（KITA）.（2）the adsorption of the kitasamycin tartrate molecularly imprinted polymer towards the target molecule is spontaneous endothermic behavior,which is consistent with the Langmuir isotherm adsorption model and the pseudo second-order kinetic model.and the maximum adsorption capacity of the imprinted polymer is126.9952 mg g^-1.The results of selective adsorption experiments showed that MIP_KITA has good class-specific adsorption capacity for the template molecule KITA and its structural analogs tilmicosin phosphate（TIL）and tylosin tartrate（TYL）.4.Combined with high performance liquid chromatography,under the optimal conditions,trace amounts of target in three animal food samples（pork,chicken,beef）was analyzed with self-made imprinted solid phase extraction cartridges which respectively used the two macrolides antibiotic imprinted polymers as fillers.The results showed that the two imprinted solid phase extraction columns have high efficiency of separation and enrichment for the template（tylosin tartrate and kitasamycin tartrate）in the actual samples,and the recovery rates were above 94%.The self-made imprinted solid phase extraction columns have good regenerability with the recovery rate did not decrease significantly after 30 cyclles of adsorption desorption experiment.