how to remove tannic acid

[ym3142]

we are using Agilent Eclipse XDBC8 column with 35% buffer with KH2PO4 and Octanesulfonate pH=2.1 and 65%MeOH mobile phase. We found the Tannic acid introduced as the counter ion of our active ingredient base was wased out of our column at 2min but with 5 min long tail. Does anyone of you have the experience working on Tannic acid or Tannate and know the good way to wash off Tannic acid or Tannate ?

[Mark Tracy]

Tannic acid is not a single compound, but a complex mixture with one major component. That is why it tails forever.

I can think of two ways to remove it from your sample, but the effect on recovery is hard to predict. One is to use a Dionex OnGuard-P cartridge that binds tannins by multiple hydrogen bonds. (It was invented specifically to remove tannins from red wine prior to IC analysis.) The other is to use an anion exchange membrane; Empore disks or similar.

[ym3142]

Mark, Thank you so much for your suggestions. So far I can only make the tail smaller. I am not sure how this small tail(almost even like a base line) will effect our accuracy and such and such tests.
But my question is how both methods you suggested can remove tannic acid selectively without remove my other actives assuming my other actives contain either OH or N. I do not think we can tolerate any loss of the actives. Thank you anyway, Have a nice weekend,