Preparation Of Metal-organic Frame Materials And Its Application In Food Sample Pretreatment

In recent years,with the development of material science,a variety of new MOFs materials have emerged in an endless stream,which has injected new vitality into solid phase extraction technology.It is expected that the discovery and use of new MOFs materials can achieve the purpose of enrichment and separation of target substances from complex sample matrix.Therefore,the development and application of new MOFs materials in new fields are of great significance.This thesis aims to explore the development potential of new metal-organic frame materials as new solid-phase extraction materials in food safety test sample pretreatment,and successfully prepared three new metal-organic frame materials.Combined with high performance liquid tandem mass spectrometer（HPLC-MS/MS）,it has been successfully applied to the pretreatment of new red in beverages,plant growth regulators and quinolone antibiotics in fruits and vegetables.1.A novel solid-phase extraction column filler-metal-organic frame material,UIO-66-NH₂,was prepared and a solid-phase extraction-high performance liquid chromatography-tandem mass spectrometry（SPE-HPLC-MS/MS）method was developed for the determination of new red in beverages.The morphology,chemical structure and adsorption properties of the nanomaterials were characterized by scanning electron microscopy,infrared spectroscopy and N₂adsorption-desorption isotherms.The solid phase extraction column was prepared by dry loading and the extraction conditions were optimized.The SPE-HPLC-MS/MS method developed in this study is simple,rapid,sensitive,and the loaded SPE column can be reused,which proves that the developed SPE column based on Ui O-66-NH₂can be used as a high-quality adsorption material for the detection of new red in beverages.The limit of detection（LOD）and limit of quantification（LOQ）were 0.05 mg/L and 0.15 mg/L,respectively.The recoveries were 91.3%-101%,and the relative standard deviations（RSD）were 2.9%-11.2%.2.A magnetic MOFs composite Fe₃O₄@Ui O-66-NH₂was prepared by solvothermal synthesis and used as adsorbent for the enrichment and detection of 4-chlorophenoxyacetic acid and 2,4-D in vegetables.It was characterized by means of SEM,XRD,FT-IR,N₂-adsorption-desorption curve and VSM,and the influence factors on the adsorption of 4-chlorophenoxyacetic acid and 2,4-D were studied by using isothermal adsorption model and kinetic adsorption model.Finally,the method was successfully applied to the detection of 4-chlorophenoxyacetic acid and 2,4-D in vegetables,showing the potential application of Fe₃O₄@Ui O-66-NH₂material in the pretreatment of food samples.3.The regulation of adsorption properties of adsorbent based on the two-ligand strategy provides a new idea for the preparation of novel MOFs materials.Two ligands（2-methylimidazole with nitrogen ligand and terephthalic acid with carboxylic acid ligand）were selected to optimize the ratio of the two organic ligands.The magnetic two-ligand MOFs composite Fe₃O4@Zn-MOF₁was prepared and successfully applied to the detection of 6 quinolone antibiotics in food.The morphology,chemical structure and adsorption properties of the synthesized Fe₃O4@Zn-MOF₁composites were characterized by SEM,XRD,N₂-adsorption-desorption curve,etc.The adsorption isotherm and adsorption kinetics were studied.The results show that the Fe₃O₄@Zn-MOF₁composite has a large specific surface area and good superparamagnetism,and has good adsorption performance for six quinolone antibiotics.Moreover,the magnetic composite material can be quickly separated and recycled by simple magnetic separation.