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Application of Diazonium Salts for Grafting the Sol-gel Based Sorbents: A New Approach Towards Unbreakable SPME

Bayat, Parisa | 2012

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 43742 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Bagheri, Habib
  7. Abstract:
  8. A novel application of diazonium salts for grafting the sol-gel based sorbents was sucessfully introduced. Preparation of unbrekable sorbents has been on highly demand and sough after by many researches for several years. However, there are a few achivements in this regard, but it still remains as a big challenge.Regarding to this issue, diazonium salts were sucessfully applied for functionalizing the different substrates, in which there is no limitation in selection of substrates. Different substrates, metallic and non metallic, such as copper, brass, stailess steel and PTFE were chosen to be functionalized by chemical or electrochemical reduction of 4-Amino phenyl acetic acid. Then, 3-(triethoxysilyl)propylamine (3TESPA) was selected as the precursor and the only reagent for preparation of chemicall bonded sorbent. Presence of the chemical bond, between substrate and diazonium salts and 3TMSPA is responsible for thermal and solvent stability and therefore long lifetime of the prepared sorbent. Characterization of the aryl group formation on the various substrates along with the prepared sorbents was thoroughly investigated by scanning electron microscopy (SEM) and thermal gravity analysis (TGA). One of the prepared sorbents, copper tube, was selected as a model sorbent for evaluation the developed method for on-line capillary microextraction (CME) of atrazine, ametryn and terbutryn, as model compounds, from the aquatic media. After extraction, the HPLC mobile phase was used for on-line desorption and elution of the extracted analytes from the loop through the HPLC column. Figures of merit of the developed method was also obtained in which the linearity for the analytes was in the range of 30-1000 µg L−1. The value of LOD (S/N= 3) for all analytes was 10 µg L−1 and the RSD% values (n=5) were all below 9.4% at the 500µg L−1 level. The developed method was successfully applied to tap and agricultural water samples while the relative recovery percentage obtained for the spiked tap water samples was from 80 to 94 % and for agricultural water samples was from 75 to 95 %.
  9. Keywords:
  10. Sol-Gel Method ; High Performance Liquid Chromatography ; Diazonium Salts ; Unbreakable Capillary Microextraction

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