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SEC using TFA/ACN
Posted: Fri Nov 05, 2010 10:01 am
by Nick4ffun
Anyone has experiences using TFA/ACN in size exclusion separation?
I found a few literatures, I don't know in which scenario we should consider TFA/ACN without using NaCl/water/phosphate.
thanks
Nick
Posted: Fri Nov 05, 2010 11:27 am
by HW Mueller
I had the TFA permanently change a Tosoh silica based SEC column. You may find some of several descriptions in the archives.
I tried to use TFA to prevent adsorption on the stat. phase of Mab. It turned out that phosphate buffered saline was the best mobile phase.
Posted: Fri Nov 05, 2010 10:50 pm
by Andy Alpert
SEC columns used in aqueous conditions usually have a polar coating with reasonably strong internal hydrogen bonds. Chaotropes like TFA disrupt those bonds, causing the coating to swell. The space between the coating ligands also becomes permeable. The result is that the fractionation range shifts to lower molecular weights, sometimes dramatically so. As for added organic solvent like acetonitrile, add enough of it and you'll superimpose hydrophilic interaction. The result is a reversal of the elution order, with large (polar) solutes eluting last instead of first. All of these phenomena are discussed in detail in my book chapter on SEC from 1999. You can download it from the Literature section of the PolyLC.com web site.