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Polysaccharide-Based Nanocomposites as Green Sorbents in Microextraction Methodologies

Golzari Aqda, Tahereh | 2019

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 51681 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Bagheri, Habib
  7. Abstract:
  8. This thesis is focused on the preparation and use of polysaccharides as extractive phases in various extraction methods, such as the micro solid phase extraction (µ-SPE), needle trap microextraction (NTME) and thin film microextraction (TFME).In the first research, feasibility of the online µ-SPE method using cellulose acetate (CA) fibers was investigated. For this purpose, CA fibers were prepared by electrospinning technique and then placed into µ-SPE cartridge. With this method, it was possible to simultaneously extract the drug compounds in the urine and plasma samples. The enrichment factor and limits of detection (LODs) were obtained in the range of 194-210 and 1.0-2.4 μg L-1, respectively. Precision of the developed method was also obtained which relative standard deviation percentage (RSD%) in the range of 2.6-7.9 were achieved. The relative recovery for selected drugs in the urine and plasma samples were obtained in the range of 94-105% and 85-102% respectively.In the second study, CA fibers were functionalized by a phenyltriethoxysilane with two different approaches. These fibers were tested in a NTME of chlorobenzenes as model components. In order to analyze the compounds, gas chromatography with flame ion detector was used. Under optimum conditions, the LODs (0.23-0.42 μg L-1) and precision (3-9%) of the method were evaluated. Finally, the proposed method was used for extraction of the selected analytes from water, sediment and sludge samples with appropriate recovery in the range of 94-105%.In the third study, the µ-SPE into pipette tip method was used for extraction antibiotics from the milk samples with using of starch-based nanocomposite. The detection was carried out using high performance liquid chromatography with UV detector at 220 nm wavelength. Then, the LODs (2.7–5.0 μg kg-1), the trueness (88-102%) and the precision of the method (3.3-6.1%) were obtained for the desired compounds. Finally, this method determined the amount of antibiotic residues in a variety of pasteurized and raw milk samples with an appropriate relative recovery rate in the range of 83-105%.In the fourth study, the chitosan-graphene oxide nanocomposite film was used for TFME of organophosphate pesticides in a variety of fruits and vegetables. Figure of merits such as LODs (0.5-1.5 μg kg-1), trueness (87-104%) and precision (2.1-9.7%) were obtained. Ultimately, the capability of the method using chitosan-grapenoxide nanocomposite film was evaluated for determination concentration variations in two groups of unwashed–unpeeled and peeled–washed fruit and vegetable samples with acceptable relative recoveries in the range 88-102% (RSD%<6)
  9. Keywords:
  10. Nanoporous Cellulose Acetate Fiber ; Strach-based Nanocomposite ; Chitosan Nanoparticles ; Graphen Oxide Nanocomposite ; Micro-Solid Phase Extraction ; Needle Trap Extraction ; Thin Film Microextraction

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