GC–MS Parameters
The analyses were completed
using an MPS2 autosampler (Gerstel AG) on an Agilent 7890B GC system
coupled to an Agilent 5977B mass selective detector (MSD) equipped
with the High Efficiency Source (HES) (Agilent Technologies, Basel,
Switzerland). Volatile compounds were separated on an OPTIMA FFAPplus
fused silica capillary column (polyethylene glycol nitroterephthalate,
cross-linked, 60 m × 0.25 mm × 0.5 μm film; MACHEREY-NAGEL,
Oensingen, Switzerland) with helium as the carrier gas at a constant
flow of 1 mL minThe MS settings were as follows: the transfer line was
fixed at 250 °C and the source temperature at 230 °C; the
analytes were monitored in SCAN mode between 30 and 350 amu with a
7 min solvent delay; the MS detector was switched off between 15.7
and 17.2 min to cut off the solvent peak; the gain was set at 15.
The autosampler was controlled with a Cycle Composer V.1.5.4 (CTC
Analytics, Zwingen, Switzerland) and PTV injector with Maestro1 software
V.1.4.8.14/3.5 (Gerstel AG).