Chemical analysis of samples was performed by gas chromatography
(GC) with a flame ionization detector (FID) using
a Varian CP-3800 coupled with a Varian Saturn 2000MS
ion-trap mass spectrometer (MS), both controlled by Varian
MS Workstation 6.9 software. The GC-FID/MS instrument is
equipped with two split/splitless injectors and an automatic
sampler HT250D by HTA SrL. The GC was equipped with
two columns of different polarities: CP-Wax 52 CB bonded
fused silica polar column (50 m × 0.25 mm, 0.2 μm film
thickness) from Varian, and an RTX-1 low polar column (30 m
× 0.32 mm, 0.25 μm film thickness, crossbond 100% dimethyl
polysiloxane) from Restek.