Microporous silica with nanolayer structure coated with renewable organic solvent film as a novel extracting phase: A combination of solid- and liquid-phase microextraction

A new method based on combination of solid- and liquid-phase microextraction was developed. For the first time, porous flower-like silica microstructures with nanometric layers were created on the surface of the stainless steel wire by a new facile hydrothermal process. The fiber, coated with a suitable organic solvent, was applied for microextraction of some organophosphorus pesticides from aqueous samples followed by gas chromatography-nitrogen phosphorous detection. Method detection limits were between 0.6 and 3 ng L-1. Relative standard deviations for intra- and inter-day precision were 4.4-7.3% and 5.1-7.8%, respectively. Fiber-to-fiber reproducibility for five prepared fibers was 6.3-8.4%. Tap, river and waste water samples were analyzed for evaluation of the method in real sample analysis. Relative recoveries for spiked tap, river and waste water samples were in the range of 94-101%. 89-97% and 82-103%, respectively. In addition, the method was compared with two commercial solid-phase microextraction (SPME) fibers, single drop microextraction (SDME) and liquid-phase microextraction (LPME). The present method showed higher extraction efficiency as compared with SDME, LPME and commercial SPME fibers. (C) 2012 Elsevier B.V. All rights reserved.