Determination of Phthalate Esters in Vegetable Oils Using Direct Immersion Solid-Phase Microextraction and Fast GC Coupled with Triple Quadrupole MS

A simple, low-solvent consuming and sensitive solid-phase microextraction method followed by fast GC-QqQ MS determination was developed for the qualitative and quantitative analysis of phthalates in vegetable oils. Multiple reaction monitoring (MRM) acquisition mode was applied to improve sensitivity. A rapid liquid-liquid extraction was performed using acetonitrile to remove the bulk of triglycerides, before immersing the fiber. A preliminary comparison between a polydimethylsiloxane (PDMS) and a Carbopack Z/PDMS fiber was carried out both in head-space (HS) and direct immersion extraction modes. PDMS in direct immersion extraction mode showed the best performance. The method was fully validated, obtaining good performance characteristics, and applied to analyze different vegetable oil samples.