Identification of the volatile constituents
The qualitative chemical analysis of the obtained samples was
necessary to adopt a technique making possible the separation
and identification of each component of the mixture via two
independent methods. The most appropriate equipment was
a gas chromatograph GC coupled with a Mass Spectrometry
GC–MS. In fact, this equipment could determine the chemical
structure and the molecular weight of each component. The
quantitative analysis was performed using a gas chromatograph
type Hewlett–Packard 5890-SERIES . It was equipped
with a split-splitless injector and a DB5-MS fused silica column
of 5% phenyl-methylpolysiloxane, 30 m · 0.25 mm i.d.,
film thickness 0.25 lm. The oven temperature was set at
50 C for 5 min, and then subjected to an increase of 5/min
to 250 C. The temperature of the injector and detector was
maintained at 250 C. The carrier gas is nitrogen and the auxiliary
gas is hydrogen and the air is free from all impurities.
The injection volume was 0.2 ml. The carrier gas was adjusted
to a linear velocity of 2 ml/min