Fatty acid methyl esters

I am a chemist working at Canadian Conservation Institute. I have
been working in the conservation field only for a few months and I
think you could help me. I am presently analysing fatty acids methyl
esters (FAME) from oils (linseed, poppyseed, walnut,...) on GC-MS
and I am trying to get the correct P/S ratio (methyl palmitate and
methyl stearate). I have no problem with everything but the
poppyseed oil. The ratio is supposed to be around 5 and I couldn't
get higher than 3.

The procedure I use is : 1) saponification with 0.5M KOH/MeOH (5
minutes 80 deg. C), 2) esterification with boron
trifluoride-methanol (20minutes 80 deg. C), 3) extraction with
hexane and separation on GC-MS, from 100 deg. C to 280 deg. C, 8
deg. C/minute. My detector is not saturated and I believe my
procedure to be efficient.


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                  Conservation DistList Instance 14:7
                   Distributed: Monday, July 24, 2000
                        Message Id: cdl-14-7-012
                                  ***