7


was tested over a range of 30 (minimum temperature settable in the autosampler) and 55°C, and the extraction time was set between 10 and 30 min.


In fingerprinting and profiling studies, the goal is to maximise the overall response, maximising the number of peaks detected and their intensities. The response surface (Figure 4) was built considering the cumulative area intensity of all the peaks detected. It is evident from Figure 4 that the maximum is reached at a milder temperature and shorter time using Vac- HS-SPME, while using regular-HS-SPME, a maximum is not reached even after 55°C and 30 min of extraction. The total number of peaks detected increased from ~150 to ~180 using Vac-HS-SPME.


the diffusivity through the liquid phase facilitating mass transfer at the interface.


The use of Vac-HS-SPME for untargeted studies of olive oil can importantly increase the level of information obtainable and the effectiveness of cross-sample comparison applying pattern recognition algorithms, allowing more effective markers identification for quality and authenticity studies.


Acknowledgements


This article is based upon work from COST Action CA 16215, supported by COST (European Cooperation in Science and Technology, http://www.cost.eu). SM and GP thank Supelco for providing the fibres.


Compliance with ethical standards


Note: The authors declare no competing financial interest.


Ethical Approval: The authors have declared that no ethical issues exist.


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