ionpairchromatography

[meudra]

Hi everyone,

Does anyone know the fonction off ammoniumnitrate in the next mobile phase:
- ammoniumnitrate and docusate sodium in ACN/water

Is it possible that it is used to increase the polarity off the mobile phase?

Thanks a lot

[Mark Tracy]

The ammonium ion competes for the ion-pairing reagent. It is a way to modify the selectivity. Since it works differently than either concentration of ion-pairing reagent or organic solvent, you can move peaks around. I have used sodium sulfate for a similar purpose. I have to say that ammonium nitrate is a strange choice, and I can only guess why that was chosen.