Chromatography Forum

Hello friends!
i work with fish oil.
I do analysis of fatty acids. fames
Now I have a new challenge, analyze cholesterol fish oil.
I have tried to carry out the method of AOAC 994.10
but I have problems.
the peaks both cholesterol and 5 alpha cholestane are not defining me very well.
I do the analysis in gc-fid with a methyl silicone column series quadrex.007
I use a liner with glass wool.
I use a temperature ramp to 170 ° C 1min 7 º C / min 261 10 min 15 ° c / min 320 ° C 7 min (total time: 35 min) detector 350 º C carrier: helium 22.4 psi detector gas: hydrogen 40ml/min Air 400ml/min, injector 340 ° C. injection 1ul
I use a perkin elmer clarus 500.
How the calculations are performed for this analysis?
Do they have some method for the preparation of these samples?
What liner should I use?
Can anyone help me with TotalChrom to load with calibration curve?

thanks for your reply!!

I haven't assayed cholesterol in maybe 20 years. I did use cholestane as internal standard and I did make trimethylsilyl derivative of cholesterol (cholestane does not derivatize). Yes, I did use capillary GC. And the assay worked well.

Back then the "official" method used benzene to extract, we used toluene. Don't know what any current or newer methods use.