Chromatography Forum

Hi all,

we have a method which we use ammonium acetate as the mobile phase and use sulphonated polymer diluted in water through a sax column. We are using UV detection. We seem to be retaining the sulphonated polymer on the column and are getting no peaks. Anyone have any idea why or indeed how we can get it off the column without damaging it?

x

You may not be able to get it off the column.

Things to try:

- increase the concentration of ammonium acetate
- add a salt of a polyvalent anion t (e.g., sulfate) to the mobile phase
- try adding some organic solvent to the mobile phase (if your polymer is only lightly sulfonated, retention may be partially due to hydrophobicity.

For future use, a weak anion exchanger may be a better choice, because that will let you manipulate the charge on the stationary phase by varying the pH.