Volatile Fatty Acid Analysis

[niekyvanveggel]

Hi all,

I'm having a bit of trouble deciding which HPLC column to use for my research.

I will be running a fermentation experiment and want to analyse supernatants for the presence of acetic, propionic and butyric acid. The mobile fase will be H2SO4, and for a detector I am planning to use UV. I have been looking at the Bio-Rad Aminex HPX-87H and the Phenomenex Rezex ROA. The problem is this: I can find a lot of comparable research that uses the Aminex column, and none that described using the Rezex. However, seeing as that the Rezex is about £600 cheaper and I am on a very tight budget, it would be very nice if I could go for that one.

Can you guys give me any leads on which would be a good choice, and, in case it is the Rezex, perhaps one or two references to literature (my supervisor will need refs before I can even mention using the Rezex...)

Thanks a lot in advance!!

Nieky

[Peter Apps]

This would probably be much easier by gas chromatography - do you have the hardware ?

Peter

[niekyvanveggel]

Yes we have, but the GC has been set up and calibrated for polyunsaturated fatty acid analysis, which I will be running simultaneously, so using the HPLC is rather essential, since both machines have an autosampler so I can let them run overnight and don't have to waste time.

[JelmerD]

Nieky,

I am currently working with this Rezex OA column and it seems to be working quite fine. We're not only using it to separate acetic, propionic and butyric acid, but also citric, pyruvic, malic, succinic, fumaric, lactic and formic acid. Because we don't run this application routinely, I can't say if the Phenomenex column will last as long as the BioRad one (or maybe it will last even longer).
Sadly I can't provide you with any literature refs... One more thing worth mentioning: if you need to measure in the low ppm-range, consider a conductivity detector instead of a UV. You would also need a chemical suppressor then.

[XL]

Dionex has at least two HPLC columns that separate the acids you mentioned above. Related separations can be found in the attached links.

1. Acclaim Organic Acid [ http://www.dionex.com/en-us/webdocs/259 ... OA_V22.pdf See Figure 6]

2. Acclaim Mixed-Mode WAX-1 [ http://www.dionex.com/en-us/webdocs/488 ... 021407.pdf See Figure 7]

Hope it will help.