2.9 Gas chromatography-mass spectrometry (GS-MS) analysis
Analysis was carried out on an Agilent GC 7820A coupled to a MS 5977B, equipped with a split/spitless injector and a DB-Fatwax UI column (30 m x 250 μm x 0.25 μm). The operation parameters were: 1 µL injection, split ratio 20:1 for FAMEs and alcohol samples and 10:1 for acetates, injector temperature 220 °C, constant flow 1 mL/min of helium, oven ramp 80°C for 1 min, 20 °C/min to 150°C, then 1°C/min to 200°C, then 20°C/min to 230°C. MS was scanning between m/z 30 and 350. For compound identification, reference standards were purchased from Pherobank, and retention times together with mass spectra were compared to the sample of interest. Quantification was made based on 6 points calibration curves. Visual inspection of chromatograms was performed using MassHunter Qualitative Analysis Navigator B.08.00 (Agilent), while quantification was performed using MS Quantitative Analysis (Quant-My-Way) (Agilent).