Innovative sol-gel coatings for solid-phase microextraction: development of fibers for the determination of polycyclic aromatic hydrocarbons at trace level in water

Innovative solid-phase microextraction coatings synthesized by sol-gel technology were developed for the determination of environmental pollutants, i.e. polycyclic aromatic hydrocarbons at trace level in water. The fibers obtained, based on the use of (3-aminopropyl)triethoxysilane and diethoxydiphenylsilane were characterised in terms of film thickness, porosity, thermal stability and pH resistance. An excellent thermal stability was obtained in the case of diethoxydiphenylsilane-based coating, with a negligible weight loss until 400 degrees C. A very good fiber-to-fiber and batch-to-batch repeatability was also obtained with RSD lower than 6% using a mixture of aromatic hydrocarbons in the low ng/l range. Finally, the capabilities of the developed coating for sampling polycyclic aromatic hydrocarbons in water at trace levels were proved obtaining limits of detection about twofold lower than those achieved by using the commercially available polydimethylsiloxane 7 mu m fiber.