it's not clear why you do not want to fractionnate, since it is the easiest method and classique.However, there are other ways to do it. Personally, I separated and quantified the different classes of polar lipids, for example, by the HPLC method, coupled to an ELSD. For more information, these two references could provide you more answers. As for your question about the use of GC-MS, this technique could help to separate different classes of sterols, if you have a database of course, allowing you to identify the different picks obtained.

http://link.springer.com/article/10.1007%2Fs11746-006-1237-4

http://www.sciencedirect.com/science/article/pii/S0176161716300244

Dear Fatma Bejaoui, thank you so much for the answer and the link

. I have run HPLC using ODS column and Methanol and water gradients as moving phase, but unfortunately the result not good, only one pick I could got. but my HPLC not occupied with ELSD.

I read some articles, its very hard to fractioned lipid to get pure compounds, so I plan to measure the lipid species and buy some commercial  to test its activity. Since my compounds is hexane extract is any change for me to found any fatty acid, glycolipid in my sample..? because if it only sterols cold detect with GC-MS , i afraid will lost some information.

Dear all, the best method to differenciate the lipid types is a combination of 1H and 13C NMR. Neutral and polar lipids as well as glycolipids and phospholipids can be analysed. Sterols and polyphenols as well. NMR is a good tool to analyse DHA and EPA quantitatively.

Dear Bernd Diehl

Thank for the information。 When i‘m running NMR for my lipid extrcat， is i need to fracinated the sample first 。。？is it any reference or article could give me advance explanation。？ Thank you

Dear Agusman,

first a NMR tests on the whole extract is ok, later one can seperate the lipid  by several methods. Yust send me some ml, I can run NMR for free. pleaes look at the following address for information and shipping.

http://www.spectralservice.de/index.php/the_company.html

Dear Bernd Diehl

Thanks you so much for your kindness and warm responded as well as over a hand to analyst my sample. Its mean to me, since I have only a few gram of sample and should be save some for bioassay. I dont know weather one gram is enough to analyst using NMR. But the offering is worth it and interesting. I will discuss with my professor and will inform you. Thank you so much for you kindness