Peak tailing at cation exchange column

[Reinhard]

Dear all!

I am doing qualyty control of flourocholine (exactly: the Cl-salt) with a Supelcosil SCX (cation exchange column). My problem is the peak shape, which shows a really high tailing (USP factor ~5).
My eluent is sodiumphosphate at pH 4.5.
As I am not experienced in ion chromatography and don´t know how to better up the peak shape in this mechanism (i want to reach at least tailing faktor 2 or smaller).

please tell me your opinion

thx

Reini

[Uwe Neue]

The problem could simply be that phosphate does not buffer at this pH. If you want to stick with this pH, use acetate. Otherwise go to pH 2.5 or 7 with phosphate.