2.7. Chemical analysis by CG
After probe sampling, the collected condensates were placed
inside small glasses under inert atmosphere (N2) to avoid degradation
and stored in a refrigerator. The samples were analyzed
twice by gas chromatography using the procedure developed by
Gottschau [2] as follows: the condensates were heated at 333K
for 15–20 min in a heat chamber to provide a homogeneous mixture.
The samples (20–30 mg) were diluted in 1 ml of a standard
solution (1.0 mg/ml squalan) prepared in proportion (1:1 v/v)
with n-Hexane (pa., Merck-Darmstadt) and acetone (pa., MerckDarmstadt).
Then, 1 l of the solution was injected into a HP 5890
gas chromatograph equipped with a capillary column and a FID
detector. The column was a 30 m × 0.245 mm ID fused silica open
tubular column coated with 0.25 m (5%-Phenyl Methylpolysiloxane,
J&W Scientific, Model: DB-05). Nitrogen was used as the
carrier gas, and the following temperature program was used: oven
temperature 343; 343–523 (25K/min); 523–623K (4K/min); and
15 min at 623K. The detector temperature was 633K. The temperature
program and the capillary column used to analyze the fatty
acids, squalene and tocopherols have proved to be very efficient.