volitile buffer conc. on mass loadibilility

[jiang295]

do you think increase of buffer conc(like TFA, formate, acetate) at the same pH will increase loadibility of basic compounds? if so, what is the highest conc we can use for prep separation?
thanks a lot.

[Uwe Neue]

For basic compounds at acidic pH, the key factor is the mutual repulsion of the adsorbed ions. Buffer concetration will increase the loadability to some degree, but you should not expect any miracles.

Here is publication that is worth reading:
U. D. Neue, T. E. Wheat, J. R. Mazzeo, C. B. Mazza, J. Y. Cavanaugh, F. Xia, D. M. Diehl, “Differences in the preparative loadability between the charged and uncharged form of ionizable compoundsâ€

[jiang295]

my sample consists all kinds of analytes, so I cannot adjust ph to alkaline condition even if my column can allow me to do so. Because i expected under basic condition, acidic compounds will suffer from decreased loadability...


[quote="Uwe Neue"]For basic compounds at acidic pH, the key factor is the mutual repulsion of the adsorbed ions. Buffer concetration will increase the loadability to some degree, but you should not expect any miracles.

Here is publication that is worth reading:
U. D. Neue, T. E. Wheat, J. R. Mazzeo, C. B. Mazza, J. Y. Cavanaugh, F. Xia, D. M. Diehl, “Differences in the preparative loadability between the charged and uncharged form of ionizable compoundsâ€