| In this paper, a series of magnetic cyclodextrin materials were developed for adsorption of organochlorine pollutants. These materials were used in magnetic solid phase extraction(MSPE) dispersion solid phase extraction(d SPE) and automated solid phase extraction. Based on this, several simpe and rboust methods for simultaneous analysis of organochlorine pollutants(highly chlorinated polychlorinated biphenyls and chlorobenzenes) in environmental samples were developed.The details are as follow. Firstly, the detection of highly chlorinated polychlorinated biphenyls in soil is based on the fact that magnetic carbon nanotube material was used for enrichment and the magnetically multifunctional purifying material was used for clean up. The magnetic solid phase extraction(MSPE) was combined with dispersion solid phase extraction(d SPE) in the pre-treatment process. The assay method of highly chlorinated polychlorinated biphenyls in seafood is based on the multifunctional magnetic mesoporous material, which was synthesized by was prepared by grafting carboxymethyl- β-cyclodextrin(CM-β-CD) on the surface of amino functionalized mesoporous Fe3O4@m Si O2 nanoparticles. The amino functionalized mesoporous surface of Si O2 can remove most of matrix interference in fish. Moreover, CM-β-CD has stronger host-guest complexation with DDT, DDE, and DDD. Based on this principle, a robust and rapid gas chromatography-mass spectrometry(GC-MS) method coupling with Fe3O4@m Si O2-NH2-CMCD as clean-up adsorbent for d SPE was developed for the analysis of several highly chlorinated PCBs in fish sample. The assay method of chlorobenzenes(CBs) residues in soil samples based on a novel β-cyclodextrin functionalized meso-/macroporous Fe3O4@flower Ti O2 absorbent as extraction material combined with gaschromatography mass-spectrometry.The aboved analytic methods largely lower the experiment cost, simplify the experimental steps, and improve the detection sensitivity and selectivity.The study of the thesis is performed as the following fields: 1. Employment of magnetic multiwalled carbon nanotube composite and magnetically multifunctional purifying material for determination of toxic highly chlorinated polychlorinated biphenyls at trace levels in soil samplesIn this study, we developed effective magnetic multiwalled carbon nanotube composite for separation and enrichment organic pollutants and the magnetically multifunctional purifying material for efficient removal of matrix interferences, especially certain organochlorine pesticide(DDT,DDE,and DDD), during the determination of toxic highly chlorinated polychlorinated biphenyls(PCBs) at trace levels in soil samples. The multifunctional adsorbent(CMCD-NH2-MNPs) was prepared by grafting carboxymethyl- β-cyclodextrin on the surface of amino-functionalized magnetite(Fe3O4) nanoparticles. CMCD-NH2-MNPs has stronger hostguest complexation with DDT, DDE, and DDD, but the same adsorbent shows weaker adsorption ability toward highly chlorinated PCBs(from tetra- to octa-chlorinated PCBs) owing to their steric hindrance effect. Based on this principle, a simple and rapid gas chromatographymass spectrometry(GC-MS) method was developed for six indicator PCBs(PCB28, PCB52, PCB101, PCB138, PCB153, and PCB180) in soil. Comparative studies were conducted to determine the clean-up efficiency of the following three techniques: i) Oasis-HLB, ii) multilayer silica column, and iii) d SPE employing CMCD-NH2-MNPs. The results indicate that CMCD-NH2-MNPs as the purification material can easily and effectively remove DDT, DDE, and DDD in soil samples within a short duration of time. The recoveries for highly chlorinated PCBs were in the range of 85.4–102.2%, with RSDs varying between1.0 and 6.5%. The proposed method was verified as one of the most effective clean-up procedures for the analysis of highly chlorinated PCBs in real soil samples. 2. Application of multifunctional magnetic mesoporous material for fish samples clean-up prior to the determination of highly chlorinated polychlorinated biphenylsIn this study, we developed a highly effective clean-up adsorbent for eliminating the matrix interferences, especially main organochlorine pesticides residues(such as p,p’-DDD, p,p’-DDE, and p,p’-DDT) during the determination of highly chlorinated polychlorinated biphenyls(PCBs) in fish samples. The multifunctional adsorbent(Fe3O4@m Si O2-NH2-CMCD) was prepared by grafting carboxymethyl- β-cyclodextrin(CM-β-CD) on the surface of amino functionalized mesoporous Fe3O4@m Si O2 nanoparticles. The amino functionalized mesoporous surface of Si O2 can remove most of matrix interference in fish. Moreover, CM-β-CD has stronger hostguest complexation with DDT, DDE, and DDD. However it shows weaker adsorption ability toward highly chlorinated PCBs(from tetra- to octa-chlorinated PCBs) due to steric hindrance effect. Based on this principle, a robust and rapid gas chromatography-mass spectrometry(GCMS) method coupling with Fe3O4@m Si O2-NH2-CMCD as clean-up adsorbent for d SPE was developed for the analysis of several highly chlorinated PCBs in fish sample. The results indicate that Fe3O4@m Si O2-NH2-CMCD as the purification material can easily and effectively remove matrix interferences in fish samples within a short time. The recoveries for PCBs were in the range of 88.4–103.2%, with RSDs varying between 1.3 and 5.7%. The proposed method was verified as one of the most effective clean-up procedures for the analysis of highly chlorinated PCBs in real fish samples. 3. A novel functionalized meso-/macroporous Fe3O4@flower Ti O2 absorbent as extraction material combined with gas-chromatography mass-spectrometry for chlorobenzenes analysis in soilA high-performance and selective absorbent was developed for simultaneous extraction of 6 kinds of chlorobenzenes(CBs) residues in soil samples by using magnetic solid phase extraction(MSPE) combined with automated SPE method followed by gas-chromatography mass-spectrometry. The adsorbent(Fe3O4@f Ti O2-CMCD) was synthesized by grafting carboxymethyl-β-cyclodextrin on the surface of porous core-shell magnetic Fe3O4@flower like Ti O2 microspheres as carrier. The absorbent exhibited higher loading capacity(25.6 mg·g-1 for 1,3-dichlorobenzene) and low matrix interfere. This maybe due to that the meso-/macroporous Ti O2 with higher specific surface area, as carrier of β-cyclodextrin film,could obviously increase the amount of recognition sites. It also has good selectivity towards chlorobenzenes based on the host-guest interaction between β-CD(on the surface of absorbent) and the targets, which can minimize complex matrix interference in soil. The main factors(amount of the adsorbent, adsorption time, elution solvent, volume of the elution solvent and elution flow rate) affecting the extraction efficiency were investigated in detail. The proposed method was successfully applied for the analysis of environmental soil samples with recoveries ranging from 87.3 to 104.3% with correlation coefficients(R) higher than 0.996. The limits of quantitation for the 6 CBs were 0.03–0.09 μg·kg-1. It was confirmed that the meso-/macroporous-structure Fe3O4@f Ti O2-CMCD was a kind of highly effective extraction materials used for the trace CBs analyses in complex soils. |
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