A comprehensive study on the effect of vacuum of targeted volatile compounds on HSSPME in a complex matrix: A softer efficient method to profile olive oil aromas

Headspace Solid-phase microextraction (HSSPME) is an easy, effective and selective technique for the analysis of volatiles and semi-volatiles compounds. Nevertheless, frequently a long time is requested to reach the equilibrium condition to maximize the extraction efficiency, thus pre equilibrium conditions are preferred as a compromise in term of throughput and sensitivity. Sampling under vacuum demonstrated an increasing extraction kinetics of analytes with a low affinity for the headspace without amplifying the temperature and thus preserving sensitive compounds.
In this work Vacuum-SPME has been investigated for the first time for the analysis of a fat matrix, namely olive oil and deodorized oil with added standards, for understanding behavior of volatiles under vacuum.
Gas chromatography coupled to a single quadrupole mass spectrometry was used for the final determination. A three variables (k= 3; temperature, extraction time and sample mass) inscribed rotatable central composite experimental design was used to optimize the sampling conditions. First analyses shown confirming effect of vacuum. Then, the work was oriented on lower temperature and extraction times conditions in order to highlight the gain of extraction rates in softer conditions, especially for semi- and lower volatiles.
A series of compounds, covering the entire range of volatility and a wide chemical structure, were selected from olive oil to compare atmospheric and under vacuum conditions while another series were chosen in the same way to be added in deodorized oil.
Advance analyses results made it possible to highlight patterns and thus to give explanation different observe phenomena concordant with theory.