Total free fatty acids, fatty acid alkyl esters and squalene were
quantitatively analyzed by gas chromatography in a Thermo Trace
GC ULTRA, equipped with a flame ionization detector (FID) and a
split injector. The injector and detector temperatures were set at
280 C. The split flow was set at 134 ml min1
. The analytical column
was a TR-Biodiesel (F) from Thermo Unicam. 0.5 lL sample
volume was injected by means of an automatic injector TriPlus.
Helium was used as carrier at a constant flow of 2 ml min1
. The
oven temperature program was 230 C for 13 min. Peak identification
was carried out using known standards (oleic acid and squalene,
Sigma–Aldrich). Methyl-heptadecanoate (Fluka) was used as
the internal standard (IS). The data were processed with the
Chrom-Card software.