Chromatography Forum

I am having a lot of problems with the Prevail Carbohydrate ES column. We recently injected a beer sample with the aim of quantifying the monomeric and oligomeric compounds using 80 to 65% acetonitrile as mobile phase. We could see a lot of late eluting compounds (could be oligomers?) and a few monomers. After this injection no peaks were visible any more, even from the standards. This column is supposed to be able to handle 100% aqueous flushing according to the manufacturers. So, I slowly increased to water and then rinsed it with water for a while. The next day I slowly went back to 80% acetonitrile and ran standards again and they were visible. However, now the retention time of the glucose standard peak decreased with each injection. The same happened with later injected samples to the point where resolution seemed to be very poor.

Another problem we have with this column is that it tends to bind certain sugars to such an extent that they do not elute from the column. Especially arabinose is a problem and we've found the same problem with manno-oligosaccarides. I generally get the idea one can run only very uncomplicated standard-like samples on this column without having problems. The manufacturers advertise it as very versatile and rugged because it is a polymer-based amino column rather than silica. I do not believe this to be true at all or am I missing something? Has anyone else had the same problems?

are you doing any type of SPE, sample cleaning or extraction?
for many food applications it is a must before you can inject your sample on your column

Thanks for replying. These samples were treated with perchloric acid to precipitate proteins, followed by KOH neutralization and filtration. Is there a specific sample clean-up you would recommend for this kind of analysis where we need to look at mono- and oligosaccharides?

I am now quite sure that the washing with water containing 0.005M TFA stripped the column, because the retention time of glucose changed from 9 minutes to 4.5 minutes after this procedure. According to the manufacturers of the column it can be used at 100% water in pH range 1-12. I don't see why this stripping effect took place. Anyway, I won't try it again. It's just such a waste. If I'd only known this before I would not have tried it. The pamflet coming with the column actually recommends washing the column with 0.01M Nitric acid. So, what I did was much more gentle.

there is very little that the manufacturer is ready to tell about those columns
it is some kind of polymer phase hybrid silica, and they do not say much more then that.
from the info it does not say if there is any other chemistry in it
from the applications it looks like a HILIC type column
have you look in the user manual provided with the column?