Determination Of Off-odour Substances In Water By Solid Phase Microextraction Of Modified Fiber Coating Based On MOFs

Geosmin（GSM）and 2-methylisobcamol（2-MIB）are one of the main causes of odors in water.Although the odors in water are not harmful to human health,they can cause dissatisfaction.The qualitative expression of"normal odor and peculiar odor"is given in the Hygienic Standard for Drinking Water（GB 5749-2022）,and the limit values of 2-methylisobcamol and geosin are added in Appendix A(both of which are10 ng L^-1).Solid phase microextraction（SPME）is one of the most effective ways to enrich GSM and 2-MIB,which are trace organic compounds commonly found in water.If a new coating can be used compared to commercial SPEM coatings,fiber coatings can be significantly cheaper and more reusable and targeted.That would be groundbreaking.Metal-organic framework（MOFs）,also known as porous coordination polymers（PCPs）,is a class of crystalline porous polymer materials formed by the coordination of metal ions/clusters and organic bridging ligands,which are formed by the combination of clusters or inorganic metal ions with organic ligands.Due to their unique properties,such as hierarchical structure,permanent porosity,high adsorption capacity and large specific surface area,MOFs are widely used in adsorption,drug delivery,electrochemical applications,etc.Among various MOFs,UIO-66-NH₂has a large window and specific surface area,significant thermal stability and excellent chemical stability to a variety of solvents,which make UIO66-NH₂ have good adsorption properties.In addition,the porous carbon derived from UIO66-NH₂ has a good pore structure and changes its hydrophobic property,which plays a good adsorption and enrichment role for weakly polar organic matter in adsorbed water.Based on this,a variety of materials represented by UIO66-NH₂@PAC and UIO66-NH₂@PAC derived carbon were synthesized in this paper,and analyzed and characterized by means of X-ray powder diffraction,transmission electron microscopy,Raman spectroscopy,nitrogen adsorption,etc.The extraction efficiency and stability of GSM and 2-MIB as solid phase microextraction coating in GC-MS analysis were studied.This paper is divided into four parts:The first chapter mainly summarizes the introduction of GSM and 2-methylisobcamol,the application principle of solid phase microextraction,the research progress of metal-organic skeleton materials and their composites,carbonized derivatives,and the significance of the research of this topic.The second chapter introduces the preparation of dual-function activated carbon composite based on UIO66-NH₂ and its carbonated porous carbon derived,and a series of characterization of the material to explore its morphology,structure,degree of carbonation,stability and other physical and chemical properties,and the material is combined with stainless steel wire into solid phase extraction fiber,and then assembled into a solid phase microextraction sample.In Chapter 3,the application of prepared solid phase microextraction fibers in the extraction of weak polar organic matter 2-MIB and GSM in water was introduced.In this chapter,a complete experimental process is designed,including the configuration of standard solution,the drawing of standard curve,the parameter setting of gas chromatography-mass spectrometry instrument,sample pretreatment methods and conditional experiments,so as to explore the optimal extraction performance of materials.In the fourth chapter,the properties of several composites and derived materials are summarized in detail,and the remarkable effects and excellent properties of fiber resolid phase microextraction are fully described.