Preparation Of Restricted Access Media-Magnetic Molecularly Imprinted Materials And Application In The Analysis Of Biological Samples

Molecularly imprinted polymers have been widely used in various fields due to their unique structure predictability,recognition specificity and wide application.In this paper,the metal-organic framework（MIL-NH₂-125（Ti））and polyglycidyl methacrylate(P_GMA-EGDMA)were used as substrates,and fluoroquinolones were prepared by using the technology of reversible addition fragmentation chain transfer.In addition,thiamphenicol magnetic molecularly imprinted polymers with Fe₃O₄ coated with poly4-chloromethylstyrene(P_VBC-DVB)as a matrix were prepared.By grafting hydrophilic functional monomers and cross-linking bovine serum on the molecularly imprinted surface,a restricted access medium imprinted polymer and a magnetic restricted access medium molecularly imprinted are obtained.Through adsorption kinetics,isothermal adsorption,selectivity and hydrophilicity evaluation experiments,the adsorption performance of molecular imprinting of restricted-access media and magnetic restricted-access media and the ability to eliminate matrix interference were studied.Secondly,several main parameters were optimized（p H of sample solution,amount of adsorbent,adsorption time and volume ratio of elution solvent）.A satisfactory linear correlation,a good limits of detection and a higher recovery rate were obtained.The research results show that the molecularly imprinted materials we prepared have broad prospects in the direct detection of antibiotic residues in complex samples.1.Restricted access media-imprinted nanomaterials based on a metal–organic framework for highly selective extraction of fluoroquinolones in milk and river waterA new type of restricted access media-imprinted nanomaterials（RAM-MIPs）were successfully prepared on the surface of metal-organic framework by reversible addition fragmentation chain transfer polymerization technology.Then it was applied as a dispersed solid phase extraction（DSPE）material in analysis of fluoroquinolones（ofloxacin,pefloxacin,norfloxacin,enrofloxacin and gatifloxacin）in untreated milk and river water by HPLC-UV detection.The resulted material has a good binding amounts(60.81 mg g^-1),rapid binding kinetic（15?min）and satisfactory selectivity as well as has a good ability to eliminate matrix interference.Several major factors affecting DSPE efficiency,p H of sample solution,dosage of RAM-MIPs,adsorption time and volume ratios of elution solvent were primarily optimized.In optimization conditions,RAM-MIPs-DSPE was combined with HPLC-UV to enrich fluoroquinolones in untreated milk and river water,achieving satisfactory linear correlation（R²>0.9988）,good limits of detection(LOD,1.02-3.15μg L^-1 for milk and 0.93-2.87μg L^-1for river water)and better recoveries（80.7-103.5%and 85.1-105.9%with relative standard deviation（RSD）of not higher than 5.3%and 4.7%for milk and river water samples,respectively）.The research results illustrate that it provides a simple and efficient method for the direct detection of FQs in complex samples.2.Preparation and performance analysis of monodisperse Glycidyl Methacrylate modified restricted access media-imprinted materialsUsing monodisperse polyglycidyl methacrylate as the matrix,ofloxacin template molecule through reversible addition fragmentation chain transfer polymerization technology,and cross-linked BSA on its surface,successfully prepared a new type of restricted access medium Imprinted Nanomaterials（MIPs@BSA）.Then it was applied to Dispersive Solid Phase Extraction（DSPE）to analyze the fluoroquinolones in the untreated egg samples by HPLC-UV detection.Finally,a good binding amount(40.72 mg g^-1),fast binding kinetics（25 min）,satisfactory selectivity and good ability to eliminate matrix interference were obtained.In order to obtain the best results,several main factors affecting DSPE efficiency,p H value of sample solution,MIPs@BSA dosage,adsorpt time and volume ratio of elution solvent are mainly optimized.Under optimized conditions,MIPs@BSA-DSPE were combined with HPLC-UV to enrich fluoroquinolones in untreated eggs,obtaining satisfactory linear correlation（R²>0.9995）and good detection limits(LOD,1.31-3.15μg L^-1)and higher recovery（89.5-96.8%）.The research results show that the restricted-access material we prepared has broad prospects in the direct detection of antibiotics in complex samples.3.Detection of thiamphenicol in fish by restricted access media-magnetic molecularly imprinted materialsIn this chapter,Fe₃O₄ coated with poly-4-chloromethylstyrene is used as the magnetic core,and RAFT technology is used,where thiamphenicol is used as the template molecule,and GMA is the hydrophilic functional monomer to prepare a highly magnetic restricted access medium molecule.Imprinted polymer.Using the prepared material as a magnetic solid phase extraction agent,an efficient sample pretreatment program of RAM-MMIPs-DSPE was established,and then combined with HPLC-UV,it was successfully applied to the detection of thiamphenicol in fish.Compared with traditional incubation extraction,ultrasonic-assisted extraction of template molecules has the advantages of faster extraction rate and shorter time-consuming.Compared with other materials,the material has a simple preparation process,is more green and environmentally friendly,the thickness of the imprinting layer is uniform and controllable,the adsorption speed is fast,the binding capacity is large,and the regeneration performance is good.In addition,the established RAM-MMIPs-MSPE method has low detection limit(2.0μg L^-1),high recovery rate（89.1-96.3%）,and good accuracy（RSD<5.4）.It has broad application prospects in the sample pretreatment process.