Chemically deposited sol-gel films on porous TiO2 nanotube arrays as an unbreakable solid phase microextraction fiber

A novel technique to improve the performance of solid phase microextraction fibers was proposed by chemical deposition of polydimethylsiloxane film on modified TiO2 nanotube array substrate. Two different techniques, the self-assembled monolayer of 3-mercaptopropyl trimethoxysilane and NaOH treatment, were compared to modify the surface of substrates. The best results were obtained with the fiber modified by NaOH 10 M. The morphology of the prepared fibers was studied by scanning electron microscopy. Also, thermal stability experiments demonstrated that the novel fiber was very stable at the temperature of 280 °C and it could be used for more than 80 times without obvious decrease in the extraction performance.The novel fiber was used for the headspace solid-phase microextraction of some aromatic hydrocarbons as the model coupled with GC-MS. The results showed that optimized extraction temperature, time and salt content were 30 ºC, 20 min and 25% (w/v), respectively. Finally, extraction performance of the prepared fiber was compared with commercially available fibers and previously reported similar fiber. The proposed method was successfully applied for determination of polycyclic aromatic hydrocarbons in river water samples with good relative recoveries from 75.8 to 104.5% and the relative standard deviation values for all analytes were below 12%.

Keywords:

polycyclic aromatic hydrocarbons , Sol-gel , Solid phase microextraction , TiO2 nanotube array