https://doi.org/10.3390/antibiotics12010177
“The analyses of the volatile compounds were performed on a GC-3800 Varian gas chromatograph coupled to a Varian MS-4000 mass spectrometer using electron impact and hooked to NIST and ABREG libraries. The constituents of the volatile oils were identified by comparing their GC retention times, LRI and the MS fragmentation pattern with those of other EOs of known composition, with pure compounds and by matching the MS fragmentation patterns and retention indices with the above-mentioned mass spectra libraries and with literature data [47]. The GC conditions were the same as reported for GC analysis (Section 3.3) and the same column was used. The MS conditions were instead as follows: ionisation voltage, 70 eV; emission current, 10 µAmp; scan rate, 1 scan/s; mass range, 40–400 Da; trap temperature, 150 °C, transfer line temperature, 300 °C. A mixture of aliphatic hydrocarbons (C8–C24) in hexane was injected under the above temperature program to calculate the arithmetic indices [12].”