A novel multiwalled carbon nanotubes – cyclodextrin nanocomposite for the Solid-Phase Microextraction–Gas Chromatography–Mass Spectrometry determination of polycyclic aromatic hydrocarbons in snow samples

Novel solid-phase microextraction coatings based on the use of multiwalled carbon nanotube-cyclodextrin (MWCNTs-CD) nanocomposites were developed for the determination of 16-priority polycyclic aromatic hydrocarbons at ultra-trace levels in snow samples. The performance of both β- and γ-CD was tested to increase the detection capabilities towards the heaviest and most lipophilic compounds, i.e., five- and six-rings PAHs. To facilitate the interactions of MWCNTs with CDs, an oxidation procedure using both HNO3 and H2O2 was applied, obtaining superior results using MWCNTs-H2O2-γ-CD fiber. Detection and quantitation limits below 0.7 and 2.3 ng/L, RSD lower than 21% and recovery rates in the 88(±2)–119.8(±0.4) % proved the reliability of the developed method for the determination of PAHs at ultra-trace levels. The complexation capability of the γ-CD was also demonstrated in solution by NMR and fluorescence spectroscopy studies and at solid state by XRD analysis. Finally, snow samples collected in the ski area of Dolomiti di Brenta were analyzed, showing a different distribution of the 16 priority PAHs, being naphthalene, phenanthrene, fluoranthene and pyrene the only compounds detected in all the analyzed samples.