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Modified Polystyrene Based Sorbents for Extraction of Trace Organic Pollutants with a Wide Range of Polarity

Zeinali, Shakiba | 2019

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 52106 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Bagheri, Habib
  7. Abstract:
  8. The main focus of this thesis is based on surface modification of polystyrene in order to prepare extractive phases appropriate for extraction of analytes with a wide polarity range. This goal was achieved by increasing surface polarity. In fact, improved wettability and the possibility of interaction with polar analytes after addition of functional groups on polystyrene surface were the main reason for increased extraction capacity. In the first research, different functional groups including amine, nitro, carboxyl and acetyl were added on polystyrene particles by chemical bonding and to investigate their influence on extraction process, 22 analytes with a wide polarity range (LogP=-2 to +7) were chosen. Prepared sorbents were packed inside a cartridge and extraction was done by on-line solid phase microextraction with similar condition for all analytes. For better comparison, three commercial sorbents including LiChrolut EN, Amberlit XAD-4 and Oasis HLB were chosen. Obtained data were analyzed using t-test, PCA and HCA to give a better understanding of the comparison. After comparing extraction capacity of sorbents with statistical methods, it was shown that carboxyl modified polystyrene revealed better extraction capacity in general, and in wide polarity range this sorbent extracted more analytes more efficiently, regardless of their polarity. The observation confirmed the potential applicability of carboxyl modified polystyrene for comprehensive extraction of analytes for non-target analysis methods. Relative standard deviations for synthesis and analysis in different days confirmed the repeatability of the method and relative recovery values for 22 analytes ranged between 70-104%, approving the applicability of the proposed method for analysis of complex matrix.In the second research, magnetic polystyrene particles were prepared. The experience of the first research confirmed that amine-modified polystyrene is capable of improving extraction of analytes with acidic functional groups. According to this, amine groups were attached to magnetic polystyrene particles. Synthesized sorbents were applied for magnetic solid phase extraction of non-steroidal anti-inflammatory drugs in urine samples. Drugs were chosen according to their polarity to cover a wide polarity range. Aspirin, salicylic acid, ibuprofen, diclofenac and mefenamic acid were chosen as analytes and naproxen as internal standard. Influential parameters were optimized using CCD method and linear dynamic range was calculated between 0.5 and 1000 µg L-1.Detection limit of method was between 0.3 and 1 µg L-1 for different analytes and relative standard deviations including intra-day, inter-day and synthesis-to-synthesis were below 12%. Finally urine sample from treated volunteers were analyzed and acceptable relative recovery values confirmed the applicability of method for rela sample analysis
  9. Keywords:
  10. Polystyrene ; Surface Modification ; Magnetic Polystyrene ; Micro-Solid Phase Extraction ; Magnetic Micro-solid Phase Extraction ; Comprehensive Extraction ; Non-Target Analysis

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