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An Interior Needle Trap by Electropolymerized Pyrrole-based Coating for Headspace Solid-Phase Dynamic Extraction of Chlorobenzenes and Their Determination with Gas Chromatography-Mass Spectrometry

Taromi Rad, Faezeh | 2009

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 40277 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Bagheri, Habib
  7. Abstract:
  8. Chlorinated benzenes are a group of cyclic aromatic compounds which are used mainly as intermediates in the synthesis of pesticides and other chemicals. These compounds have harmful effects on human health, as on blood, kidneys, skin and eyes, and cause biological disorders and cancers. Chlorobenzenes have been ranked as priority pollutants by the US Environmental Protection Agency (EPA). The permissible level of these compounds for drinking water ranges between 2 μg/L and 1 mg/L. Hence determination of these compounds is of a significant importance. Solid Phase Dynamic Extraction (SPDE) of 5 types of chlorobenzenes (monochlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene and 1,2,3,4-tetrachlorobenzene) from headspace of aqueous solutions was implemented by an electropolimerized polypyrrole absorbent coated on internal surface of a Needle-Trap Device (NTD). Presence of π-π interactions between polypyrrole and aromatic compounds prospects acceptable efficiency for polypyrrol adsorbent in extraction of these compounds. A prepolymerization solution was prepared and transmitted in a needle and applying a distinct voltage concurrently, which resulted polypyrrole coated in the internal surface of the needle. Then, with the help of a peristaltic pump, this needle trap was used for headspace extraction of chlorobenzenes from aqueous solutions in a batch system. Compounds were desorbed by thermal desorption using gas chromatograph with FID detector. Extraction time and temperature, flow rate of analyte pumped in the needle trap, NaCl concentration percentage in the extraction solution, and desorption temperature were optimized. Therefore, GC-MS data was used to achieve more tender analytical parameters. Achieved detection limits of monochlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene and 1,2,3,4-tetrachlorobenzene were respectively 500 ng/L, 250 ng/L, and 50 ng/L for the last three compounds. Linear ranges of these compounds were attained respectively 500-5000 ng/L, 250-2500 ng/L, and 50-500 ng/L for the last compounds. Achieved RSDs (n=3) of this method for these 5 compounds were: monchlorobenzene 5.4%, 1,4-dichlorobenzene 6.9%, 1,2,3-trichlorobenzene 6.0%, 1,2,4-trichlorobenzene 13.0% and 1,2,3,4-tetrachlorobenzene 6.3%.
  9. Keywords:
  10. Chlorobenzene ; Neadle Trap ; Polypyrrole ; Needle Trap Extraction ; Head Space-Solide Phase Dynamic Extraction ; Solid Phase Dynamic Microextraction

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