Oxidized single-walled carbon nanohorns as sorbent for porous hollow fiber direct immersion solid-phase microextraction for the determination of triazines in waters
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This paper evaluates the potential of oxidized single-walled carbon nanohorns (o-SWNHs) immobilized on the pores of a hollow fiber (HF) for the direct immersion solid-phase microextraction of triazines from waters. The fabrication of the device requires the oxidation of the nanoparticles by means of microwave irradiation in order to obtain a homogeneous dispersion in methanol. Then, a porous hollow fiber is immersed in the methanolic dispersion of the o-SWNHs under ultrasound stirring. This procedure permits the immobilization of the o-SWNHs in the pores of the hollow fiber. For the extraction, a stainless steel wire was introduced inside the fiber to allow the vertical immersion of the o-SWNHs-HF in the aqueous standard/water sample. The triazines were preconcentrated on the immobilized o-SWNHs and further eluted using 150 μL of methanol. The solvent was evaporated and the residue reconstituted in 10 μL of methanol for sensitivity enhancement. Gas chromatography–mass spectrometry was selected as instrumental technique. The limits of detection were between 0.05 and 0.1 μg L−1 with an excellent precision (expressed as relative standard deviation) between runs (below 10.2 %) and between fibers (below 12.8 %). Finally, the method was applied to the determination of the triazines in fortified waters, an average recovery value of 90 % being obtained.
KeywordsOxidized single-walled carbon nanohorns Hollow fiber Solid-phase microextraction Triazines Waters
Financial support from the Spanish DGICyT (Grant CTQ2011-23790) and Junta de Andalucía (Excellence project P09-FQM-4801) are acknowledged. J.M.J.S. wishes to thanks the Spanish Ministry of Education for the predoctoral award AP2007-02597.
Conflicts of interest
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