sample other than vegetable oil were extract using Soxhlet apparatus with petrol ether as a solvent prior to esterification
in the case of direct extraction without prior treatment with diluted HCL some tissue sample gave lower yield in total fat content
but there was no significant difference in fatty acid
profile. The separation of FAMEs in the chromatogram was optimized
by adjusting the starting temperature of the column oven
and the rate of the temperature program. Table 1 shows the optimization
of the method on DB-225ms column due to the resolution
of elaidic and oleic acid.
The first temperature program was used before optimization of
vegetable oil analysis. It was noticed that a faster temperature rate
gave better resolution between critical pair elaidic and oleic acid
therefore the starting temperature was lowered to 60 C and the
temperature rate of 7 C/min was applied. Such conditions are considered
as an optimum because, in contrast to analytical standards,
the samples are comprised of two or three major peaks and their
high concentrations reduce resolution. To speed up the analysis
on DB-23 the column carrier gas flow was raised to 1.5 mL/min.
An even faster flow rate may be applied if the resolution of cis/trans
isomers is not obligatory.
3.2. Method validation
3.2.1. Specificity
Specificity of the method was evaluated by recording chr