By Dodo on Wednesday, January 29, 2003 - 06:40 pm:
Hi. I am doing some research work on fatty acid. I have chosen innowax column, 30 meter, 0.25 mm, 0.25 micron.
My problem is, I cannot get good separation for fatty acid mixture C6-C22. C22 acid refused to come out with each injection.
My temperature programme: 60C (0.3 min), 120-250C at 10C/min, 250C (10 min). Gas flow: 1.8ml/ constant flow. 1 microliter injection, split 40.
What other way I can adopt to get good separation? Ideally, I would like some advice on the temperature programme, i don't want to increase the column isotherm temperature beyond 250C.
Thanks.
Dodo
By Molever on Thursday, January 30, 2003 - 06:39 am:
I work for a major soap company; make methyl esters from the fatty acids for good chromatography and good separation of saturates from unsaturates. The column you possess should be fine, but we use a Supelco 2330 or Restek RTx-2330 type as they less affected by oxygen degradation with heat over time.
By jos vloet on Friday, January 31, 2003 - 12:43 am:
I never met that problem. I'am using a FFAP (15x0.53;df=1) and all acids are separated up to C24.
Oven: 120C-- 10 C/min-- 240 C -- 20 minutes
Injector: 260C (or with temp. program.)
The quantitation/validation results are good.
By ornel on Tuesday, March 23, 2004 - 01:54 am:
Hi. Soon I will also work on fatty acids.At the moment I am doing some literature research. I would like to know how you have prepared your mixture? Did you mix all of the acids in methanol?
By Consumer Products Guy on Thursday, March 25, 2004 - 12:08 pm:
Dissolve fatty acids or soaps in 12% boron trifluoride-methanol or sulfuric acid-methanol in volumetric flask, heat on steam bath 5 minutes, cool, add petroleum ether, swirl, add saturated sodium chloride solution, invert, let separate, inject top layer.