A Peer Inter-laboratory Study of SPME-GC-FID/MS Method for theAnalysis of Volatile Compounds in Virgin Olive Oils for Supporting Panel Test: Extracted Conclusions and Future Directions

The sensory assessment of virgin olive oils is officially carried out by a sensory panel that identifies positive and negative sensory attributes to classify the oils according to their quality grades, namely extra virgin (EV), virgin (V) and lampante (L). The workload of sensory panels, the limited number of them and the need for a confirmative robust classification, particularly in borderline oils (EV vs. V, V vs. L), has led to the search of instrumental methods supporting the sensory assessment. In this context, the identification and quantification of volatile compounds responsible for sensory attributes of virgin olive oil by solid phase microextraction-gas chromatography-flame ionization detector/mass spectrometry (SPME-GC–FID/MS) has been tested in an inter-laboratory approach analyzing the same samples, identifying the same compounds, and implementing the same quantification procedure. In this work, 7 laboratories participated and the information provided by them were differentiated according to the detectorthat they used, FID or MS. Linearity, repeatability, reproducibility, recovery and limits of detectionand quantification were studied. Additionally, the laboratories tested three alternative strategies of quantification, all based on calibration curves, and the results were compared. The limits of detection and quantification were also studied by means of more than one method to analyze themost representative ways to measure the signal to noise ratio at low concentration. The discussion allowed implementing some improvements of the protocol towards a full validation process. This work was developed in the context of the project OLEUM “Advanced solutions forassuring authenticity and quality of olive oil at global scale“ funded by the European Commission within the Horizon 2020 Programme (2014–2020, grant agreement no. 635690)