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Aminex mobile phase alternatives?

Posted: Mon Feb 18, 2019 9:55 pm
by mor9ena
Hi.
I have been working with Aminex HPX87H columns for fermentation analysis for very long time, using photodiode array (PDA) and refraction index detectors, with H2SO4 as mobile phase.
In order to transfer the column method to a system incorporating PDA and QDa detectors (Waters, MS, electrospray), I wonder if it is possible to replace the mobile phase with some other acid, more compatible with this detector, since sulphuric causes ion supression. I thought of formic acid, but I don't know if it affects the resin somehow or saturates the column.
Any thoughts?

Re: Aminex mobile phase alternatives?

Posted: Tue Feb 19, 2019 9:36 pm
by tom jupille
Ion suppression in the mobile phase is the whole point behind using sulfuric acid. What you want is a strong acid that is not very hydrophobic (so it doesn't stick to the resin), which pretty much limits you to mineral acids.

You might try TFA, but I'd advise doing on an expendable column.