Vacuum-assisted and multi-cumulative trapping coupled with GC×GC for highly informative virgin olive oil volatile profiling

In this study, we assessed vacuum (Vac) and multiple cumulative trapping (MCT) in headspace solid-phase microextraction (HS-SPME) as potential alternative or combined methods for highly informative virgin olive oil volatile profiling. All three techniques, i.e., Vac-HS-SPME, MCT-HS-SPME, and Vac-MCT-HS-SPME, demonstrated enhanced extraction performance for semi-volatiles. The synergistic combination of Vac and MCT exhibited up to a 5-fold increase in extraction efficiency for less volatile compounds. Integrating these techniques with comprehensive multidimensional gas chromatography (GC×GC) facilitated a thorough analysis of the volatilome.

Initially, we examined 18 targeted quality markers, previously identified through traditional HS-SPME-GC-MS, to compare the performance of the three techniques and later to assess their effectiveness in categorizing virgin olive oil in its commercial categories. Using the proposed alternative techniques, the selected markers provided biased results towards geographical origin over the commercial categories, while using the data matrices in an untargeted way allowed for a less biased clusterization based on the commercial categories. Notably, no misclassifications were observed, except for one instance where one extra virgin olive oil was erroneously classified as virgin olive oil in the 3×10 min Vac-MCT-HS-SPME method.

The use of these approaches is very easily implementable, and it is highly promising, especially for the characterization of less-volatile analytes.