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Solid-phase Microextraction of BTEXs by Sol-Gel-Based Trimethoxy Silyl Propyl Methacrylate Fiber

Soltannezhad dizaji, Mahda | 2009

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 39881 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Bagheri, Habib
  7. Abstract:
  8. Conventional solid phase microextraction fibers posses relatively low recommended operating temperature, instability and swelling in organic solvents, breakage of the fiber, stripping of coatings, and bending of the needle. Some of these problems have been obviated by covalent bonding of the polymer phase to the fused-silica substrate by sol-gel technology, but the easy breakage of the fiber still is a remaining challenge In this work, after successful fabrication of unbreakable SPME fibers based on 3-(trimethoxysilyl)propyl methacrylate precursor deposited on the surface of copper wire, the same approach was carried out to synthesis new sol-gel based SPME fibers. Three different coated fibers including 3-(trimethoxysilyl)propyl methacrylate (3TMSPMA), tetramethoxysilane (TMOS), (trimetoxysilyl) propyl amine (TMSPA) were prepared. The efficiency of prepared sorbents was investigated using a laboratory-made SPME device and gas chromatography with mass spectrometry (GC-MS) for the extraction of BTEXs from the headspace of aqueous samples. Fiber with 3-(trimethoxysilyl)propyl methacrylate precursor was found to be superior over other polymers. These fibers are unbreakable, inexpensive, and durable and can be prepared simply. They are mechanically stable and exhibits relatively high thermal stability (up to 260 °C). Important parameters influencing the extraction process were optimized and an extraction time of 10 min at 30 °C gave maximum peak area, when the aqueous sample was added with NaCl (15% w/v). At the optimum conditions, detection limits for the studied compounds were between 0.001-0.003 ng/ml and RSD values were 6.3 – 11.1% (n=3).
  9. Keywords:
  10. Solid Phase Microextraction ; Sol-Gel Method ; Electrochemical Deposition ; BTEX ; Head Space-Solide Phase Dynamic Extraction

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