Novel multiwalled carbon nanotubes-polyaniline composite film coated platinum wire for headspace solid-phase microextraction and gas chromatographic determination of phenolic compounds.

A novel multiwalled carbon nanotubes-polyaniline composite (MWCNTs-PANI) film coated platinum wire was fabricated through electrochemical deposition. The coating was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectrophotometry and thermogravimetry. It was found that the coating was porous and had large specific area and adsorption capacity; in the composite MWCNTs and polyaniline interacted with each other and the film kept stable up to 320 degrees C. The as-made fiber was used for the headspace solid-phase microextraction (HS-SPME) of some phenolic compounds (i.e. 2-chlorophenol, 2,4-dichlorophenol, 2-methylphenol, 3-methylphenol, 2,6-dimethylphenol, 2-nitrophenol), followed by gas chromatographic analysis. The MWCNTs-PANI coating showed better analytical performance than PANI. Under the optimized conditions, the detection limits were 1.89-65.9 ng L(-1), the relative standard deviations (RSDs) were 2.7-6.5% for six successive measurements with single fiber, the RSDs for fiber-to-fiber were 5.2-12.4%, the linear ranges exceeded two magnitudes with correlation coefficient above 0.992. The fiber could be used for more than 250 times without decrease of efficiency. The proposed method was successfully applied to the extraction and determination of phenolic compounds in water sample, and the recoveries were 87.7-111.5% for different analytes. In addition, the fiber also presented advantages of easy preparation and low cost. Therefore, it is a promising SPME fiber.