Hi Roberto,

You can try BP-21 from SGE (http://www.sge.com/products/columns/gc-columns/bp21-ffap). It has been designed for FFA and it works very well for grape and wine analysis.

Good luck

Cheers

Guillaume

We work on  HP model 6890 chromatograph equipped with a silica capillary column of 30 meters length, 0.32 mm internal diameter, film 0.2 mm thick, Supelco brand, model SP 2340.

Hi Roberto,

You can also use 15 m X 0.53mm ID X 0.50 micro m Nukol (acidified PEG)  are good for free fatty acids.This column is capable of separating both short  and long chain fatty acids in excellent peak shape with minimal adsorption. You can run temperature program from 100- 220 C with GC-FID.

Good luck

Hi Roberto,

I work on Agilent Tech. model 7890A chromatograph with silica capillary column HP 88 J&W scientific series - 100mx0.25mmx0.20um film thickness.

It works very well.

Good luck

Hi Julio,

Perkin Elmer Clarus 500 GC, USA fitted with an FFAP elite column (30 m length × 0.32 mm i.d. × 0.25 μm film thickness) would be suitable for fatty acid analysis. 

All the best.

Thanks.

Hi Julio

We used Glass column: Length 1.80 cm x ¼ inch internal diameter, packed with 10 per cent diethylene glycol succinate (DEGS) on 80 to 100 Chromosorb W.

It works well.

But, more importantly, the way you prepare FAME and the programming of the machine matters.

All the best

Dear colleagues,

Thank you very much to you all for your responses, it will be very useful for our group

I can see that some of the columns you are using are appropriated for both derivatized and non derivatized free fatty acids

FFA in diary products can be conveniently quantified by means of derivatization with Trimethylsilyl diazomethane solution. In this way you is able to quantify only the free fatty acids by using a high polar GC column (such as SP 2560 supelco). Nevertheless, normally, in diary products the FFA are in a very low quantity with respect to the esterified fatty acids, for this reason I suggest that you preventively to separate them by means of a SPE silica cartridge.

Dear Andrea,

Thanks for your answer 

I agree with you that a separation of FFA from dairy fat is essential before GC analysis, but we are exploring the possibility of making the chromatographic run of FFA without any previous derivatization, and for this reason I would like to know columns types recommended for that purpose.

Dear Julio,

I understood your question, in this regard the responses of the colleagues are excellent and I wish you success.

Please excuse my insistence but, I think that the best method for analysis of FFA in dairy products is the derivatization with diazomethane after SPE separation; it's easy e allow you to use the same GC column that you use for the esterified fatty acids; these columns are excellent and let you get an excellent separation of some isomers fundamental for the analysis of dairy products, such as C18:1 trans and cis isomers C16:1 trans and cis isomers C18:2 isomers and so on.

thank you for your attention

I wish you a good job

Dear Andrea

Thanks a lot for your advice. I only knew about derivatization using alcohol/sulfuric acid. We will read more about the method you are mentioning for derivatization. Is this reaction of derivatization with Trimethylsilyl diazomethane quantitative? We have standards of FFA (not derivatized), and for quantification purposes we think that we can only use them for calibration curves as long as the derivatization reaction is quantitative, and thus all FFA in the standard is converted to FAME.

Agree with Andrea, but at the same time Diazomethane is extremely hazardous  to use. You can only use ether solution of diazomethane.If you are thinking of derivatization of FFA, you may better use BF3/methanol solution  for excellent  derivatization. 

Agree with Abdur. Diazomethane is very hazardous due to very difficult "generation". For this reason I use a product from Sigma: trimethylsilyl-diazomethane 2.0M hexane solution (cod. product 362832); You can find the procedure in Serra et al. (Meat Science 97 (2014) 504–512). Regarding to the internal standard in my opinion is better to use a free fatty acid; you must be careful to volatile fatty acids, so I suggest to use more than one internal standard: one for the determination of volatile fatty acid (C5:0 or C9:0; if you use the C9:0 you must calculate the correction factors due to the fact that C9:0 is not so volatile as C:4 and C:6). For the determination of the no-volatiles fatty acid you could use C19:0.

greetings. Andrea

According to internal standard in dairy product, i use C17:0 and i had never problem. For fa in cheese many publications mention a mix of FA as describe Andrea Serra in previous post.