Preparation Of Nano Fe₃O₄ Surface Imprinted Magnetic Particles And Its Application In Magnetic Extraction

As the key technology for enrichment,separation and analysis of toxic and harmful substances in food,environmental and biological samples,sample pretreatment technology has attracted much attention.Because of the high recovery rate,less dosage of organic solvent,and the separation is fast and simple,the new method magnetic solid phase extraction?MSPE? which used to extract low content component in complex samples has received wide attention and developed fast in recent years.In this method,selection of functional magnetic particles directly determines the efficiency of harmful substances preconcentration and separation in the sample.Therefore,it is very important to select a kind of high efficient adsorption material in magnetic solid phase extraction.In this paper,we applied molecular imprinting technique on the surface of the composite magnetic material in the preparation of molecularly imprinted polymer,as a resulet,we prepared magnetic molecular imprinted polymers which have specific recognition properties of molecular imprinting polymer and magnetic response of magnetic material.The polymers were used as adsorbent for magnetic solid phase extraction in the pretreatment for actual cosmetic samples.The synthesized magnetic molecular imprinted polymers were characterized by FT-IR?XRD?VSM and TGA.By optimizing the extraction conditions,develop a fast,high sensitivity of quantitative method to detect low content component in hair coloring samples by magnetic solid phase extraction followed by high performance liquid chromatography.The method is simple,rapid,with good selectivity and high sensitivity.The main contents are as follows:?1?Use 1-naphthol as template molecule to synthesis core shell molecular imprinted polymeric magnetic particles.The materials were characterized by Fourier transform infrared absorption spectroscopy,X-ray diffraction,magnetization curves and thermogravimetric analysis.Optimize extraction conditions,use the particle material as magnetic solid phase extraction sorbent for adsorption of 1-naphthol and 2-naphthol in hair coloring samples.By high performance liquid chromatography analysis,establish a highly selective analysis method to detect naphthols in hair coloring agent.The experimental results show that the liner range were 0.02-25 mg kg^-1 for 1-naphthol and 2-naphthol in hair coloring products,the linear relationship is good?R²=1?,the detection limits?S/N=3?were 0.006 mg kg^-1.The intra and inter day precision are less than 9.3,whic accord with the demands of quantitative analysis,meet the requirements of quantitative analysis of naphthols in Hair Coloring sample.?2?Double modification of SiO₂ and MPS in the surface of nano Fe₃O₄ respectively,use p-aminophenol as template to synthesis molecularly imprinted polymers on modificated nano Fe₃O₄ particles surface,and then prepare magnetic polymer particles of p-aminophenol by molecular imprinting.Characterized physical morphology,thermal stability and chemical structure of the magnetic particles.Optimize extraction conditions of adsorption time,sample volume,analytical time,eluent type,eluent volume,solution acidity and salinity,establish a method of MSPE-HPLC to separate and analyze aminophrnol in hair coloring agents.The experimental results show p-aminophenol and m-aminophenol have a good linear relationship in the range of 0.06-50 mg kg^-1 and 0.08-50 mg kg^-1(with R² of 0.9989 or 0.9983),the detection limits?S/N=3?were 0.018 and 0.024 mg kg^-1,the intra and inter day precision is good?RSD?7.7?,which supply a new method for separating and analyzing aminophenol in hair coloring sample.?3?Using p-aminophenol as template molecule to prepare magnetic molecular imprinted polymers.Use two common aminophenol---p-aminophenol and m-aminophenol as object,respectively.The adsorption kinetics of p-aminophenol and m-aminophenol were observed at30?,and the adsorption thermodynamic behavior of p-aminophenol and m-aminophenol at30-60?were investigated by magnetic molecular imprinted polymers.The experimental results were fit with the kinetic and isothermal adsorption curve simulation,showing the superiority adsorption properties of magnetic molecular imprinted polymer on the synthesis of two kinds of aminophenol in the hair coloring products.