Gas chromatography-mass spectrometry analysis
(GC/MS)
GC/MS analyses were performed on a Thermo Fischer
capillary gas chromatograph directly coupled to the mass
spectrometer system (model GC ULTRA S/N 20062969;
PolarisQ S/N 210729). HP-5MS non polar fused silica
capillary column (50 m x 0.32 mm, 1.25 μm film
thickness) was used under the following conditions: oven
temperature program from 40°C (2 min) to 280°C at
5°C/min, and the final temperature kept for 10 min; injector
temperature 250°C; carrier gas He, flow rate 1mL/min; the
volume of injected sample was 1.5μl of diluted oil in
hexane; splitless injection technique; ionization energy
70eV, in the electronic ionization (EI) mode; ion source
temperature 200°C; scan mass range of m/z 40-650 and
interface line temperature 300°C. The constituents of essential oils were identified based on their Kovats Index,
calculated in relation to the retention time of a series of alkanes (C4- C28) as reference products, in comparison with those of the chemical compounds gathered by Adams table[14], and the similarity of their mass spectra with those gathered in the NIST-MS library, or reported in the literature [15-16].