Chromatography Forum

Hi, all -

Are there any UPLC columns (similar to the BioRad Aminex columns) for sugar/organic acid/ethanol separations? I haven't even checked vendor websites yet, but I figured I'd ask here to see if anyone knew. I imagine this type of column is difficult to re-engineer for UPLC.

Thanks!
H_H

Yes, polymeric packings won't work in UPLC. However, packings are available with applications for sugar separations, ethanol content in fermentation broth or organic acids. If you give me the specific application needs, I can give you advice. Alternatively, you can look at the Water website, especially for applications on the UPLC Amide column, but my colleagues may have more applications than can be found there.

I think many people would like to see ANY better option for this separation. A standard LC application (i.e., using 5 um particles) would be a great improvement over these 9 um, 30 cm monsters.

There is a fairly substantial market for any option that could replace the ion exchange columns. Hey column manufacturers - put on your thinking caps and give us some ideas.

Uwe:
The ethanol (and methanol) are the biggest problem analytes in this mixture. What do you have that would give any retention for them?

We have something like this:
http://www.sielc.com/application_183.html

alcohols will retain too on this Obelisc N column - you just need to use RI detector to monitor alcohols. There is plenty of room between peaks (82% of ACN) in order to "fit in" alcohols. Obelisc N columns is mixed-mode HILIC column, so retention for ionizable compounds (acids, amino acids, amines) can be adjusted by buffer concentration, buffer pH and amount of ACN. Retention of sugars can be adjusted by amount of ACN and buffer pH (our phase is less polar at lower pH than at higher pH - 2 vs. 5-7). Between amount of ACN, buffer pH, buffer concentration and buffer nature I am sure you can find conditions where everything is separated.
Retention time changes because of change in ionization state of compounds and stationary phase when you play with pH of the mobile phase.