Organic Acids on IC

[Levi]

If there's a forum more specifically for Ion Chromatography, please direct me. In the meantime though I'm having this problem:

I'm running organic acids on IC, and am having separation problems with regards to propionate, sulfamate, and formate blending together. I'm using a Sodium Carbonate/Bi-Carbonate eluent and have been tweaking the strengths trying to get better separation, but still haven't quite gotten a decent chromatograph. Would anyone on this board have any advice?

[randy]

What column are you using?

[Levi]

It's a Metrohm column, ASupp7 - 250 mm.
Carrier material: Polyvinyl alcohol with quarternary ammonium groups.

The flow rates are fairly specific for this column, so although I've altered them slightly, it seems to have little effect for this application. The eluent obviously has a much more drastic effect.

More specifically I guess I'm interested to find out if there are any eleuent modifiers that might be useful. (using 2% acetone also had little effect)

[tom jupille]

That separation might be better done on an ion-exclusion column.

[gcguy]

We regularly run up to 50% modifier on our Supp 5 column so you could increase that to see if ii helps. We usually use acetonitrile as the modifier just to help with the solubility of the sample.

[Levi]

Thanks for the assistance. I've managed to weaken my eluent enough to have good standard linearity and a somewhat good separation.

Very excellent board to've found, I'm sure I'll check it often.

[sassman]

For future reference, there is an IC forum here:

www.analyticalchem.com

[Markus Laeubli, Metrohm]

It's a Metrohm column, ASupp7 - 250 mm.

Please send me the chromatogram by e-mail (lae@metrohm.com).
Then I will check our experiences.