3.3. GC and GC-MS/MS Analysis of the Essential Oils

For chemical identification and quantification, 1 µL of properly diluted EOs in n-hexane (1:20, v:v) was analyzed using a gas chromatograph Varian Saturn 2100T coupled to a MS/MS Saturn 2100 ion trap mass spectrometer. The chromatographic separation was performed with the capillary column VF-5ms (30 m × 0.25 mm × 0.25 μm). The split injection mode was used (split ratio 1:20), while He 6.0 was used as carrier gas with a flow rate of 1 mL min⁻¹. The injector temperature was set to 230 °C. The initial oven temperature was set to 40 °C for 4 min, then the temperature was raised to 150 °C at a rate of 5 °C per min and held at this temperature for 13 min. In addition, the column was heated up to 200 °C at a rate of 10 °C and finally kept at 200 °C for the next 15 min. The total running time was 59 min. The mass spectra were recorded in the SCAN mode in a range from 50 to 650 m/z using electron ionization energy at 70 eV and the detector temperature was set to 150 °C. The volatile compounds were identified by comparing the mass spectra of the compounds in plant samples with those available in the NIST library and the data available in the literature.