2.7.2. GCeMS analysis
The GCeMS analysis was performed on an Agilent 6890 gas
chromatograph coupled with a 5975 mass spectrometer (Agilent
Technologies, USA). The carrier gas was helium with a flow rate of
1.1 mL/min. The separation was performed on a DB-WAX
30 m 0.25 mm 0.25 mm capillary column (Agilent Technologies,
USA). The initial oven temperature was 35 C for 1 min, which
was ramped to 100 C at the rate of 8 C/min and held for 3 min;
subsequently, the temperature was ramped to 120 C at the rate of
3 C/min and held for 2 min; finally, the temperature was ramped to
230 C at the rate of 5 C/min and held for 5 min. The mass detector
was operated at 230 C in an electron impact mode at 70 eV. The
ion-source temperature was 230 C, while the transfer line temperature
was 150 C. The chromatograms were recorded by
monitoring the total ion currents in the 20e350 mass range.