Rapid Preparation Of New Functionalized Magnetic Materials And Their Application In The Pretreatment Of Environmental Polycyclic Aromatic Hydrocarbon Samples

This paper developed new functionalized modification methods to conveniently prepare new functionalized magnetic materials,which has Stable property,excellent extraction performance and strong selectivity,apply to the enrichment and clean-up of PAHs in environmental water samples and soil samples.The main research contents are as follows:1.A time-saving method was applied to synthesize methyltrimethoxy modified magnetic mesoporous silica with?Fe₃O₄@mSi O₂-Me-PTSA?or without?Fe₃O₄@mSiO₂-Me?p-toluenesulfonic acid?PTSA?as the catalyst.The synthesized materials were systematically characterized and the results demonstrated that Fe₃O₄@mSiO₂-Me-PTSA has a relatively smaller aperture and extreme hydrophobicity?water contact angle of 135°?.Combined with gas chromatography-mass spectrometer?GC-MS?to determine PAHs,Fe₃O₄@mSiO₂-Me-PTSA had the best extraction efficiency and recovery.Under the optimized extracted conditions,the proposed method showed good linearity within the concentration range of 0.5 to 200?g L^-1 with correlation coefficients of 0.9990 to 0.9999.The LOD and LOQ based on signal-to-noise ratios of 3 and 10 were in the range of 0.005 to 0.044?g L^-1 and 0.016to 0.148?g L^-1,respectively.The PAH concentrations in environmental water sample were successfully determined using the developed method.The absolute recovery of spiked samples(5?g L^-1)ranged from 77.34%to 95.30%and RSDs were below6.24%.2.Phenyl-modified magnetic mesoporous silica?Fe₃O₄@mSiO₂-Ph-PTSA?was synthesized with p-toluenesulfonic acid?PTSA?as the catalyst and used as a selective adsorbent coupled with accelerated solvent extraction?ASE?and GC-MS for the determination of PAHs in soils.The material prepared without PTSA as the catalyst?Fe₃O₄@mSiO₂-Ph?was synthesized for comparison.The synthesized materials were first systematically characterized and evaluated and the results revealed that the grafting amount of phenyl group onto Fe₃O₄@mSiO₂-Ph-PTSA was higher than that of Fe₃O₄@mSiO₂-Ph.Hence,Fe₃O₄@mSiO₂-Ph-PTSA possessed much higher extraction efficiency than Fe₃O₄@mSiO₂-Ph.Moreover,contrast experiment showed that Fe₃O₄@mSiO₂-Ph-PTSA displayed higher selectivity towards PAHs than n-alkanes and?-?interaction played a key role in the adsorption process.In the presence of soil extractmatrix,parametersaffectingtheextractionefficiencyof Fe₃O₄@mSiO₂-Ph-PTSA for PAHs were optimized.Under the optimal conditions,the proposed method for the determination of PAHs in soils was linear in the range of5-500 ng g^-1,and correlation coefficients?R?ranged between 0.9994 and 0.9999.The limits of detection?LODs?and limits of quantification?LOQs?,which were based on signal-to-noise ratios of 3 and 10 were in the range of 0.07-0.41 ng g^-1 and 0.24-1.37ng g^-1,respectively.The developed method displayed better clean-up effect than the silica gel column method and the matrix effect markedly decreased while compared to the unclean-up condition.3.By in-situ polymerization method,polydivinylbenzene?PDVB?modified magnetic material?Fe₃O₄@PDA@PDVB?were conveniently synthesized coupled with ASE and GC-MS,for the determination of PAHs in soils.Due to PDVB owned large?-conjugated networks,Fe₃O₄@PDA@PDVB still can effectively extract PAHs under the condition of high organic phase to inhibit hydrophobic interaction.In the presence of soil extract matrix,parameters affecting the extraction efficiency for PAHs were optimized.Under the optimal conditions,the developed was liner in the range of 5-500ng g^-1?correlation coefficients>0.9993?.The limits of detection and limits of quantification,which were based on signal to noise ratio of 3 and 10,were 0.11-0.55ng g^-11 and 0.37-1.82 ng g^-1,respectively.The RSDs for inter-day and intra-day precision were below 14.59%and 11.48%,respectively.The developed method displayed better clean-up effect than silica gel column method.After clean-up,the matrix effect of BaA,BbF,BkF,BaP,IcdP,DahA and BghiP markedly decreased.