Chromatography Forum

Hi, I have to establish GC-MS-analytics of FAMEs, especially from skin in our lab.

The problem is that skin samples contain long chain fatty acids (up to C26-C27) among the shorter ones.

Does anybody has a hint for me which column's best for this task (excellent resolution of short FAMEs AND very long FAMEs in the same run)?

At the moment I'm using a 35%-phenyl-65%-dimethylpolysiloxane-column (Supelco MDN-35, 30 m, ID 0.25 mm, df 0.25 um), but I have bad resolution of the longer chain FAMEs.

And which manufacturer produces the best columns?

Thanks a lot!

Flo

Hi
I think that a polar column such as omegawax or PEG is useful.
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u can search the internet for bulletins of supelco.
I can send u bulletins of supelco.
my email:famahyari876@yahoo.com
best regards

We use cyanopropylsilicone phases for FAMEs. I think the PEG phases may not be able to go to high-enough temperatures for the long chains required here.

SP-2380 or a bonded cyanosilicone column would be a good idea for the higher carbon number FAMEs. A shorter than usual column 10-15 meters might be an excellent choice.

If a saturated and unsaturated C24-C28 FAMEs separation is not to be maximized, perhaps a Equity-1701 or a Equity 5 might be a solution.

Rod

I am analyzing Policosanols which are C20-C30 alcohols. I am using a Supelco SAC-5 30m column. I start out at 100C and ramp up to 300C in 10 minutes and maintain 300 for 15 minutes. Even the C30 alcohol elutes fine.

Best Wishes,