Preparation Of Covalent Organic Skeleton Material And Its Application In Analysis Of Trace Polycyclic Aromatic Hydrocarbons

PAHs are the most widely distributed environmental and food pollutants,which pose a great threat to human health due to their carcinogenic,teratogenic and mutagenic characteristics.In order to realize the accurate quantitative detection of trace and trace PAHs in environmental and biological samples,some sample pretreatment methods are often needed to adsorb and enrich them.solid phase extraction（SPE）technology has attracted wide attention because of its advantages of rapid,efficient and easy to operate.The adsorbent is the core of solid phase extraction technology.The excellent adsorption material can not only improve the extraction ability,but also increase the reuse rate.covalent organic framework materials（COFs）are emerging classes of crystalline porous organic polymers.due to its high stability,large specific surface area and easy functionalization,COFs materials have shown good application prospects in adsorption enrichment.This paper focuses on the preparation of COFs materials,and uses this COFs material as solid phase extractant to adsorb and enrich trace polycyclic aromatic hydrocarbons（PAHs）in real water samples,and carries out quantitative analysis in combination with gas chromatography-tandem mass spectrometry（GC-MS/MS）.The research contents are as follows:（1）Firstly,firstly,a covalent organic framework material（COF-ETDA）with double pore size was prepared by solvothermal method.the morphology and structure of the material were characterized by scanning electron microscopy and fourier transform infrared spectroscopy.he adsorption performance of pahs as solid phase extraction adsorbent was studied,and the main factors affecting solid phase extraction were optimized,including the amount of adsorbent,extraction time,elution solvent,elution time,eluent volume,and the quantitative analysis of pahs was realized in combination with GC-MS/MS.The method can obtain good linearity in a wide concentration range,and can also obtain satisfactory recovery rate when used in the detection of real samples.（2）To further simplify the extraction procedure,the following experiments used COF-ETDA filled solid phase extraction columns to detect trace polycyclic aromatic hydrocarbons（PAHs）in water samples by GC-MS/MS analysis combined with solid phase extraction instrument.effects of eluent volume,elution solvent,sample pressure,elution pressure,sample p H value on solid phase extraction efficiency were investigated.At the optimum extraction conditions,the SPE column has strong extraction ability for 16 PAHs.This method can save the ultrasonic step,and the accuracy is high,the sensitivity is good,it has certain practical value for the detection of polycyclic aromatic hydrocarbons in real samples.（3）Magnetic solid phase extraction has great advantages over traditional SPE,the COF-ETDA is coated on the surface of Fe₃O₄ nanoparticles connected with amino groups to obtain magnetic COFs materials.The successful synthesis of Fe₃O₄@Si O₂-NH₂@COFs was demonstrated by scanning electron microscopy,fourier transform infrared spectroscopy and X ray diffraction,and a new magnetic solid phase extraction method was established using this composite as an adsorbent to combine with GC-MS/MS to enrich and detect pahs in water samples.Fe₃O₄@Si O₂-NH₂@COFs was successfully applied to the magnetic solid phase extraction of polycyclic aromatic hydrocarbons in water samples by optimizing the amount of adsorbent,extraction time,sample p H value,elution solvent,and elution time.This method is simple and rapid,low cost,low detection limit and good repeatability.It is suitable for accurate quantitative detection of trace PAHs.