Preparation And Application Of Two Imprinted Polymers Based On Ionic Liquids Functional Monomer For Fluoroquinolone Antibiotics

Molecularly imprinted polymers?MIPs?have attracted much attention in the fields of solid phase extraction,biosensors and drug analysis due to their advantages such as specificity in recognition,structure predetermination,and versatility.However,most of MIPs were prepared by using highly toxic organic solvents?trichloromethane,acetonitrile,toluene etc.?,and their selectivity was damaged when they were used in aqueous phase because of the differences in water molecule interference and swelling.In addition,the highly toxic organic solvents can also pollute environment.Therefore,the development of green imprinted polymer materials which can be prepared and used in aqueous media has become the focus of many scholars.Ionic liquids are organic salts composed of anions and cations.Due to their unique properties such as non-volatile,non-flammable,good solubility and stability,and structural design,they are attracting attention as an environmentally friendly material in the fields of material preparation and separation analysis.Since cations of ionic liquids?mainly imidazoles?can provide?-electron clouds,and the side chains are easily functionalized and modified.Thus the strong interactions,such as?-?and ion dipoles between ionic liquids and target molecules will be formed,which can overcome interferes of water molecule.Consequently,the functional ionic liquids can be used as a novel functional monomer to prepare MIPs in aqueous phase.In this work,1-allyl-3-vinylimidazol chloride and 1,6-hexyl-3,3'-bis-1-vinylimidazolium bromide ionic liquids were,respectively,used as novel functional monomers,the newly ciprofloxacin hydrochloride(MIP_CPFX)and levofloxacin hydrochloride(MIP_HLVFX)imprinted polymers were prepared in a green aqueous medium on the surface of styrene divinyl-benzene.The morphology and microstructure of the two MIPs were characterized.Combined with high-performance liquid chromatography and static adsorption experiments,the adsorption characteristics of two fluoroquinolone imprinted materials were systematically investigated.Based on the above experiments,the MIPs were respectively used as solid phase extraction columns to separate and analysis trace amounts of ciprofloxacin hydrochloride and levofloxacin hydrochloride in environmental water samples,soil samples and pork samples.The results are mainly shown as follows:1.Discussing the usage,harmness and commonly detection methods of fluoroquinolones;Introducing the development and application.The using of ionic liquids in the field of molecular imprinting techniques was also introduced.2.1-Allyl-3-vinylimidazole chloride and 1,6-hexyl-3,3'-bis-1-vinylimidazolium bromide were,respectively,used as functional monomers,to synthesised ciprofloxacin(MIP_CPFX)and levofloxacin hydrochloride(MIP_HLVFX)imprinted polymers in aqueous media.Combined with UV spectral scanning,emission scanning electron microscopy,specific surface area analysis and infrared spectroscopy,the microstructure and characteris of two fluoroquinolone imprinted polymers were investigated.3.Static adsorption experiments were used to study the adsorption isotherms,adsorption thermodynamics,adsorption kinetics and selective adsorption performance of two imprinted polymers at different temperatures.The results showed that two imprinted polymers had good specific adsorption properties towards template molecules.The adsorption process was fitted to the Langmuir model,and the adsorption process proceeded spontaneously.The results of the adsorption kinetics showed that MIP_CPFXPFX and MIP_HLVFX could reach equilibrium in about 180 min and 60 minutes,respectively.The adsorption process of two MIPs was conforme to pseudo-second-order kinetics model.4.Prepared solid phase extraction cartridges by using two MIPs,respectively,and applied them to the separation and enrichment of residual target substances in actual water samples,soil samples and food samples under optimal conditions.The results showed that the solid phase extraction cartridges had the ability to selectively separate and enrich template substrate,and the recovery rate was above 80%.After 40regeneration cycles,the recovey rate was not significantly decreased.These results showed that two fluoroquinolone imprinted polymers synthesized in this work have good specific adsorption performance and regeneration.