| Solid phase microextraction (SPME) is a novel sample preparation technique based on the extraction of analytes on a polymeric coating and desorption of analytes in an analytical instrument. Polypyrrole-coated (PPY) fibers have been prepared and used for SPME in our group. The extraction properties of the PPY fiber were examined using liquid chromatography/mass spectroscopy (LC/MS). The PPY fiber was used for an in vivo pharmacokinetic study. The main concern with PPY fibers is that they are not reusable and the production process is time consuming. The purpose of the present project was to develop a fast method for the preparation of PPY fibers and to improve the reproducibility and sensitivity of the extraction of polar and aromatic compounds, such as diazepam and nordiazepam, with these fibers. It is expected that such a Technique would shorten and simplify drug-dosing studies.; In order to improve the reproducibility of PPY fibers, an electropolymerization method was optimized, in which five PPY fibers were simultaneously prepared in one vessel. The relative standard deviation of PPY fibers prepared by this method was less than 9%. Previous studies showed that adding tri(ethylene glycol) (TEG) in the polymerization step for the preparation of PPY fibers resulted in higher extraction recoveries and shorter extraction times. However, the fibers prepared by this method were not stable and fiber leaching was observed. Assuming that poly(ethylene glycol) (PEG) had the potential to develop a strong physical interaction with PPY and result in increased hydrophilicity of the coatings, PEGs with different molecular weights were examined. The results indicated that PEG did not develop a strong bond with PPY and acted as a wetting agent, which in turn was washed from the PPY fiber after the first extraction.; Another method to increase the polarity of PPY based fibers involved the preparation of N-substituted PPY coatings. Four different poly(N-substituted pyrroles), poly(N-methylpyrrole), poly(N-phenylpyrrole), poly(N-cyanoethylpyrrole), and poly(N-phenolpyrrole) fibers were synthesized, among which the poly(N-phenolpyrrole) was the smoothest and exhibited a higher extraction efficiency and longer lifetime. This fiber was successfully applied to the extraction of diazepam and nordiazepam from urine samples. |
