Sample Pretreatment Technoligy Based On Magnetic Solid-phase Extraction And Its Application On Separation Flavonoids And Analysis Polymer Additives

As we all known,the study of sample pretreatment technology in analytical chemistry is crucial.In order to improve the sensitivity,accuracy,and detection limit of analytical method,it is an important factor to separate and enrich targets from complex samples,which would avoid the interferences of impurities and matrix.Therefore,new sample pretreatment technology development has become a hot area in analytical chemistry.Magnetic solid-phase extraction(MSPE)technology is a new type of solid-phase extraction technology.Because its adsorbents are magnetic nanoparticles,the adsorbents can be easily separate from solution through an external magnet.These magnetic adsorbents can be recycled and reused.Aimed to different targets,we can design specific functionalized magnetic nanoparticles.In this work,magnetic solid-phase extraction and its application on the separation of active ingredients from natural products were studied.A new model was developed for the separation and purification of the active components from the invasive plant Mikania micrantha using the in-line"Magnetic solid-phase extraction-high speed counter-current chromatography(MSPE-HSCCC)".A type of magnetic solid phase adsorption material was synthesized and applied to the analysis of polymer additives and the migration of such additives in foods.A "Magnetic solid-phase extraction-high performance liquid chromatography(MSPE-HPLC)" analytical method was established for the trace detection of polymer additives in foods and drinks packed with plastic.The main results were as follows:1.A new separation mode for in-line "MSPE-HSCCC" was developed.By comparing the adsorption capacities of five magnetic nanoparticles for flavonoids,the most suitable Fe3O4@SiO2@DIH@EMIMLpro magnetic ionic liquid material was selected to fill the MNP column,and the device of in-line MSPE-HSCCC was constructed.The n-hexane-ethyl acetate-methanol-water(H-E-M-W,3:5:3:5,v/v)and ethyl acetate-methanol-water(E-M-W,25:1:25,v/v)solvent systems were applied for the MSPE-HSCCC process.And the latter solvent system was more suitable for simultaneously separating three flavonoids quercetin-3-O-rutinoside(95.13%),luteoloside(98.54%)and astragalin(98.19%)from Mikania micrantha.The separation and purification of active compounds in invasive plants was achieved using the in-line"magnetic solid-phase extraction-high-speed countercurrent chromatography"method.2.A magnetic metal-organic framework Fe3O4@ZIF-8 was synthesized and the method for the determination of seven polymer additives in foods and drinks packed with plastic was established by "MSPE-HPLC".The magnetic zeolitic imazolate framework-8(Fe3O4@ZIF-8)was successfully synthesized by a typical hydrothermal method.The parameters of MSPE conditions were optimized.The methodological investigation of this analytical method has good precision,stability,reproducibility and accuracy.The detection and quantification limits were 0.03-0.15 ng mL-1 and 0.08-0.50 ng mL-1,respectively.The results were better than the reported literatures.The recoveries of this method were 80.06%-119.37%(40,50,60 and 200 ng mL-1 additions)with relative standard deviations of 0.22%-5.42%.