| In magnetic solid phase extraction technology,the magnetic separation method was used to replace the filtration and centrifugal separation in the traditional solid phase extraction to separate the extractant from the extraction matrix.Compared with solid phase extraction,magnetic solid phase extraction is more convenient and rapid,and it is widely used for sample pretreatment.Biomass materials are natural products in nature,and different structures of biomass materials endow them with different physical and chemical properties.In the vast field of materials,there have been many reports on the application of biomass materials with advantages of environmental protection and economy in sample separation and analysis.The deep eutectic solvent is a"green solvent"with rich hydrogen bond network.It can be obtained by grinding or mixing and heating for a short time,and its composition is basically low or non-toxic to the human body and the environment.D eep eutectic solvents have high biocompatibility,chemical stability and functional designability.Applying deep eutectic solvents and biomass materials in magnetic solid phase extraction technology to design and synthesize deep eutectic solvents modified biomass magnetic nanomaterials as magnetic solid phase extractants will provide a new idea for the application of biomaterials and modern separation and analysis t echnology.In this study,three different deep eutectic solvent-functionalized biomass magnetic nanoparticles were designed and synthesized,which were applied to the magnetic solid phase extraction separation analysis of trypsin(Tryp)and ovalbumin(OVA).The main research contents are as follows:(1)Magnetic beads co-modified with benzyltrimethylammonium chloride/trifluoroacetamide deep eutectic solvent and?-cyclodextrin for magnetic solid phase extraction of TrypAn environmentally friendly deep eutectic solvent(DES-TB)composed of trifluoroacetamide and benzyltrimethylammonium chloride modified?-cyclodextrin(CD)grafted magnetic beads(MB-NH2@CD@DES-TB)were synthesized and used for solid phase extraction of Tryp.The extraction capacity of MB-NH2@CD@DES-TB for Tryp under the optimized extraction condition was549.87 mg·g-1.The Langmuir adsorption equilibrium was found fitted well with extraction adsorption equilibrium relation between MB-NH2@CD@DES-TB and Tryp.The absolute recovery of Tryp in Tryp standard solution was 16.8%.And the extraction capacity of MB-NH2@CD@DES-TB toward Tryp still maintained well after ten times recycling and reuse.The detection limit(LOD)and quantitative limit(LOQ)were 0.072 mg·m L-1 and 0.240 mg·m L-1 respectively.The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)showed that MB-NH2@CD@DES-TB could extract Tryp from crude bovine pancreas extracts.The MB-NH2@CD@DES-TB magnetic nanoparticles prepared in this study were expected to be an excellent solid phase extractant for extracting Tryp from real complex samples.(2)Ferroferric oxide-chitin nanomaterials modified with citric acid monohydrate/choline chloride deep eutectic solvent for the magnetic solid phase extraction of trypsinA magnetic nanocomposite material(Fe3O4-Chitin@NADES-CC)was prepared for Tryp extraction by using biomass material chitin and a natural deep eutectic solvent(citric acid monohydrate/choline chloride eutectic solvent,NADES-CC)as raw materials.Under the optimized extraction conditions,the extraction capacity of Tryp by Fe3O4-@NADES-CC was 1082.67 mg·g-1.The extraction experiment results of Fe3O4-Chitin@NADES-CC on five common proteins containing Tryp show ed that the Fe3O4-Chitin@NADES-CC had excellent selective extraction ability for Tryp.It was found that the adsorption of Tryp on the Fe 3O4-@NADES-CC surface was more in line with Langmuir adsorption theory.After screening the eluate,the reusability of Fe3O4-Chitin@NADES-CC to extract Tryp was explored.The extraction capacity of Fe3O4-Chitin@NADES-CC for Tryp was 400.23 mg·g-1.The limit of quantification and detection limit of this method were 0.266 mg·m L-1 and 0.080 mg·m L-1,respectively.The results of SDS-PAGE experiment showed that Fe3O4-Chitin@NADES-CC could extract Tryp from crude bovine pancreas extracts.The proposed method indicated that the Fe3O4-Chitin@NADES-CC magnetic nanocomposite material containing biomass material chitin provide d a new idea for the separation and analysis of Tryp in complex samples.(3)Ferroferric oxide-chitosan nanomaterial modified with deep eutectic solvent of malic acid/choline chloride for magnetic solid phase extraction of ovalbumin:A magnetic nanomaterial(Fe3O4-Chitosan@NADES-MC)was synthesized by modifing a natural deep eutectic solvent(malic acid/choline chloride deep eutectic solvent,NADES-MC)on the surface of Fe3O4-Chitosan nanocomposite and it was used for the solid extraction of OVA.Under the optimized conditions,the maximum extraction capacity of the Fe3O4-Chitosan@NADES-MC for OVA could reach 196.86mg·g-1.The extraction experiment of Fe3O4-Chitosan@NADES-MC on five common proteins fully proved the selective extraction of OVA by Fe3O4-Chitosan@NADES-MC.By fitting the adsorption isotherm model,it was found that the adsorption between OVA and Fe3O4-Chitosan@NADES-MC was a monolayer adsorption.The extraction capacity of Fe3O4-Chitosan@NADES-MC for OVA was basically maintained at 53.46 mg·g-1 after being reused 5 times.The experimenta l results of the methodology research showed that the method ha d good stability,precision and repeatability.The detection limit and the limit of quantification were0.047 mg·m L-1 and 0.014 mg·m L-1,respectively.The results of SDS-PAGE experiment proved that the extraction method could extract OVA from egg white.The Fe3O4-Chitosan@NADES-MC magnetic nanocomposite material prepared in this part of work has broad application prospects in the pretreatment of OVA samples. |
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