Preparation Of Array Microwell Stainless Steel Fiber Grafted COF And Its Application As SPME Adsorbent

Polycyclic aromatic hydrocarbons(PAHs)are at low concentration in aqueous and it is difficult to achieve the lowest detection limit of analytical instruments;therefor,appropriate sample pretreatment technology is necessary prior to separation.Solid phase microextraction(SPME)technology,which integrates sampling,extraction,and injection together,can increase the precolumn concentration of PAHs effectively and combined with gas chromatography easily.At present,commercial SPME fibers have various shortages,such as low extraction efficiency,high expenditure short life-cycle etc.The purpose of this thesis is to prepare etched stainless steel fibers grafted with covalent organic framework(COF),which has excellent extraction performance.The main achievements are summarized as follows:1.COF-TPBD-grafted fiber was fabricated and employed to preconcentrate seven PAHs including biphenyl,acenaphthylene,fluorene,anthracene,fluoranthene,pyrene,benzo[a]anthracene.A four-electrode electrochemical corrosion device was used to prepare array micropore stainless steel fiber.After the silanization treatment,the SPME fiber coated with COF-TPBD was grown and grafted in situ on the surface of fiber.The surface structure of the prepared fiber was characterized by all kinds of instruments,such as scanning electron microscopy,X-ray diffraction,energy spectroscopy,thermogravimetry etc.The prepared SPME fiber was used for the extraction of PAHs in water.The linear correlation coefficients of the seven PAHs were all above 0.98,and the detection limits for the seven PAHs were 1.0?5.0 ?g/L.The relative standard deviation(RSD)for six replicate extractions using one SPME fiber ranged from 1.7% to 9.0%.The fiber-to-fiber reproducibility for three parallel prepared fibers was 2.1%?7.2%.The recoveries for the spiked PAHs in the water samples were in the range of 87.59% ?169.92%.2.Prepare COF-TPpa coated extracted fiber,and establish SPME-GC analysis method for seven kinds of PAHs in water.The stainless steel fiber is electrochemically and silanized,the COF-TPpa material is generated by solvothermal method,and the material is grown in situ on the stainless steel fiber to prepare the extracted fiber with the coating material of COF-TPpa.Various methods were used to characterize the extracted fibers.The extracted fiber was used to enrich the seven PAHs in the water,and the SPME-GC analysis method was established.The linear correlation coefficient of the seven PAHs were all above 0.9,and the detection limit for the seven PAHs were 0.2?0.5 ?g/L.The relative standard deviation(RSD)for six replicate extractions using one SPME fiber ranged from1.9% to7.3%.and the fiber-to-fiber reproducibility was 3.6%?8.6% with three parallel prepared fibers.The recoveries for the spiked PAHs in the water samples were in the range of 96.80%?165.40%.3.Prepare extracted fiber based on COF-300 coating of etched stainless steel fiber.The stainless steel fiber is electrochemically and silanized,and COF-300 is grown in situ on the stainless steel fiber to prepare the extracted fiber with the coating material of COF-300.Various methods were used to characterize the extracted fibers.The extraction fiber was used to enrich the seven PAHs in the water,and the SPME-GC analysis method for the seven PAHs was established.The linear correlation coefficient of the seven PAHs were all above 0.9,and the detection limits for the seven PAHs were 0.1?0.5 ?g/L.The relative standard deviation(RSD)for six replicate extractions using one SPME fiber ranged from1.5% to 4.2%,the fiber-fiber relative standard deviation(RSD)for three parallel prepared fibers was 1.9%?9.4%,respectively.The recoveries for the spiked PAHs in the water samples were in the range of 99.81%?165.15%.