Chemical Forums
Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: Lizard on December 03, 2014, 12:35:09 PM
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When analysing an ionic compound via HPLC would you get two separate peaks one for the cation and one for the anion? Surely the salt will dissociate in the mobile phase?
For example N‐methyl‐N‐(propan‐2‐yl)cyclopentanamine fumarate, would have a peak corresponding to protonated N‐methyl‐N‐(propan‐2‐yl)cyclopentanamine and one corresponding to deprotonated fumaric acid?
Any help would be much appreciated.
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What type of mobile phase and stationary phase are you using?
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For a through treatment of your problem, we will need the information Babcock_Hall: asked for. However, your underlying premise may very well be flawed. If you're doing ion exchange chromatography, you might get two peaks. But if you're doing reverse phase or other column chemistry, the protonated vs non-protonated won't resolve from each other at all. Instead, you'll get mis-shapen peaks. We try to minimize ionization, or maximize, if that gives us better results. We don't try to get two species for one analyate. Otherwise, you will get horrible reproducibility.