Sudden SELECTIVE peak TAILING (carbohydrates)!?

[lc_k]

Dear G.Serena,

according to the column manufacturer my problem is unlikely to be caused by a void volume, since only one of the peaks is affected. The problem is then likely to be about chemistry. Is your problem about selective tailing or are all peaks affected?

[WillyOne]

I calibrate glucose, fructose, saccarose, lactose and maltose.
The first three are really affected. Maltose and lactose eluting quite later could be acceptable

[Vlad Orlovsky]

Assuming that this is the first time you are using this column and conditions the problem is related to nature of compounds and conditions of analysis. Your problem has nothing to do with void volume. If column forms void you will observe either splitted peak or much wider peaks for all compounds (except may be early eluters). One of my guesses would be that you are observing two epimers for two sugars. I would suggest that you try to play with pH and buffer concentration and see if t

[lc_k]

Many thanks for this interesting idea about epimers! This could be possible but would still have to be related to changed column conditions, since we had used this established method already over several months before the problem with fructose and glucose appeared. There are a couple of contact points between the dilute NaOH and stainless steel, which I am now suspecting as the cause... Does this match whit what you have observed?