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Preparation of Poly (Methacrylic Acid-ethylene Glycol Dimethacrylate) Coated Solid Phase Microextraction Fiber and Its Application for the Determination of Chlorophenols and Polychlorinated Biphenyls Coupled with Gas Chromatography

Author: LiWenChao
Tutor: YangShaoGui
School: Nanjing University
Course: Environmental Science
Keywords: solid phase microextraction poly (methacrylic acid-ethylene glycoldimethacrylate) chlorophnenol polychlorinated biphenyls water serum
CLC: X502
Type: Master's thesis
Year: 2012
Downloads: 127
Quote: 0
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Abstract


Solid phase microextraction (SPME) which was developed based on solid phase extraction is one of popular sample preparation techniques. Development of new coating material is always the research hotspot of SPME, scince some commercial fibers have several drawbacks such as lack of non-resistance to high temperature and organic solvents, high cost and short life. Poly (methacrylic acid-ethylene glycol dimethacrylate)(MAA-EGDMA) material which would appear as an ideal sorbent was used as the martial of Intube-SPME and PMME rencently for detection of basic drugs from biological samples. But both of them need additional auxiliary devices. However, there are no reports about preparation of poly (MAA-EGDMA) as SPME fiber coating.In this thesis, a novel and simple method was first developed to prepare a poly (MAA-EGDMA) coated SPME fiber using a glass capillary as a "mold" and silica fiber or steel wire as substrate. Some polymerization parameters affecting the morphology and extraction efficiency of coatings were optimized.The homemade fibers combined with gas chromatography was designed to determine chlorophnenol from water sample and polychlorinated biphenyls(PCBs) from serum sample under optimum extraction conditions. The main works of this paper are as follows:(1) A novel and simple method was first developed to prepare a poly (MAA-EGDMA) coated SPME fiber using a glass capillary as a "mold" and silica fiber as substrate. In combination with GC, the method for determination of PCBs from serum sample was proposed. The results showed that the ratio of MAA and EGDMA, polymerization solvent and polymerization time can affect the morphology and extraction efficiency of coatings.The homemade coating prepared under the optimum showed a highly cross-linked, porous and homogeneous structure, which was thermally stable up to300°C. The fiber-to-fiber reproducibility was acceptable. The extraction capability of coating can compare to85um PA commercial SPME fiber which is often used to analyze chlorphenols. Optimization of extraction conditions were extraction temperature of60°C, extraction time of50min, stir speed of1050rpm, saturated NaCl and pH of2, which were carried out by orthogonal array experimental design. Under the optimum conditions, the detection limits were in the range of0.1-10ng/L, linear range was0.2-50ng/mL for target analytes, the correlation coefficients were all greater than0.99, and relative standard deviation was less than8.9%, which could meet the practical requirements of trace analysis of environmental samples. Four cholorphenols were detected from tap water and lake water samples by using the proposed method, and the recoveries of spiked natural water samples were ranged from91.8%to110.8%and90.6%to111.4%for tap and lake water samples, respectively.(2) The adhesive mechanisms of polydopamine were applied for using steel wire as substrate to prepare poly (MAA-EGDMA) coated SPME fiber. In combination with GC-uECD, the method for determination of PCBs from serum sample was proposed. The ratio of two polymerization solvent can affect the morphology and extraction efficiency of coatings. The optimum ratio was determined by comparing the extraction efficiency of PCBs. The coating showed a porous and homogeneous structure, which was thermally stable up to280°C. The extraction capability of coating was better than30u.m PDMS commercial SPME fiber and can compare to85μm PA commercial SPME fiber. The optimum extraction coditions were dilution rate of1:2, extraction temperature of70°C, extraction time of30min, stir speed of1050rpm, desorption temperature of270°C. Coupled with GC-μECD, the method detection limits range for determination of PCBs from serum sample were1-4ng/mL, linear range was5-100ng/mL, the correlation coefficients were all greater than0.99, relative standard deviation was less than9.8%, and the recoveries of spiked serum samples were ranged from78.3%to110.6%.

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CLC: > Environmental science, safety science > Environmental pollution and its prevention > General issues > Analysis and determination of pollution
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