Direct-immersion solid-phase microextraction coupled to fast gas chromatography mass spectrometry as a purification step for polycyclic aromatic hydrocarbons determination in olive oil

Abstract

The aim of the present work was to optimize a preparation step for polycyclic aromatic hydrocarbons in a fatty extract. Solid-phase microextraction is an easy preparation technique, which allows to minimize solvent consumption and reduce sample manipulation. A Carbopack Z/polydimethylsiloxane fiber, particularly suitable for extraction of planar compounds, was employed to extract polycyclic aromatic hydrocarbons from a hexane solution obtained after a previous extraction with acetonitrile from oil, followed by a liquid-liquid partition between acetonitrile and hexane. The proposed method was a rapid and sensitive solution to reduce the interference of triglycerides saving the column life and avoiding frequent cleaning of the mass spectrometer ion source. Despite the non-quantitative extraction of polycyclic aromatic hydrocarbons from oil using acetonitrile, the signal-to-noise ratio was significantly improved obtaining a limit of detection largely below the performance criteria required by the European Union legislation.

Keywords: Direct immersion (DI); Edible oil; Gas chromatography–mass spectrometry (GC–MS); Polycyclic aromatic hydrocarbons (PAHs); Solid-phase microextraction (SPME); Zirconia-based sorbent (Z-Sep+).