Sub-ambient temperature sampling of fish volatiles using vacuum-assisted headspace solid phase microextraction: theoretical considerations and proof of conceptSub-ambient temperature sampling of fish volatiles using vacuum-assisted headspace solid phase microextraction: theoretical considerations and proof of concept Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2024-05-092022enThe extraction of volatiles from perishable food at a sub-ambient temperature using headspace solid-phase microextraction (HS-SPME) has not been considered in the past due to the corresponding loss in sensitivity. We propose HS-SPME sampling under vacuum (Vac–HS–SPME) to compensate problems of sensitivity loss and achieve substantial improvement in extraction efficiencies whilst sampling at temperatures as low as 5 °C. The approach was applied to fish samples, representing a highly vulnerable perishable food sample. The theoretical considerations explaining the performance of Vac–HS–SPME at sub-ambient temperatures are discussed and related to the increase in gas diffusivities when sampling under vacuum. A comparative study between Vac- and regular HS-SPME for the extraction of 18 compounds from salmon was carried out at different temperatures (5, 30 and 40 °C) and sampling times (10–60 min). For the majority of the compounds, Vac–HS–SPME at 5 °C yielded similar or superior extraction efficiencies than regular HS-SPME even when sampling at 40 °C. However, four compounds were better extracted at 1 atm presumably due to the intensification of competitive adsorption of analytes on the SPME fiber under vacuum or the partial losses of more volatile analytes during air-evacuation in the presence of the frozen samples. Sub-ambient temperature sampling (5 °C) combined with Vac–HS–SPME was also applied to monitor the changes in the 18 compounds present in salmon, redfish, and cod refrigerated for up to five days. The results were compared to those obtained with regular HS-SPME at 40 °C. Overall, Vac–HS–SPME sampling at 5 °C represents a new and powerful approach for the analysis of volatiles in refrigerated foods, and has a great potential for future studies in quality control and freshness assessment.This article is based upon work from the Sample Preparation Study Group and Network, supported by the Division of Analytical Chemistry of the European Chemical Society. This article is based upon work from COST Action CA 16215, supported by COST (European Cooperation in Science and Technology, http://www.cost.eu).http://creativecommons.org/licenses/by/4.0/Analytica Chimica Acta1192 Delbecque Nathalie Mascrez Steven Psyllaki Eleftheria Ψυλλακη Ελευθερια Purcaro, Giorgia Elsevier Headspace solid-phase microextraction Vacuum-assisted headspace solid-phase microextraction Fish Spoilage Sub-ambient temperature Perishable food