TFA alternatives, peptide purification

[Kostas Petritis]

It's the MS portion...

[Bryan Evans]

If better separation is required (for LC-MS), you can try a combination of acid & TFA, for ex:

0.1% HCOOH + 0.01%TFA, or
0.1% AcOH + 0.01% TFA

[TimB]

I have had very a lot of success switching from TFA to Formic acid. It works very well for Mass Spec.

[JimH]

Thanks to all for the input... Regarding the proposition of a 2-step process, I'm currently using TFA buffers then performing multiple relyophilizations in HCl. This is working satisfactorily with minimal TFA in the final product, I had just hoped to cut down time in purification. If the relyophilizations are still necessary to obtain Cl salt, the only gain in switching mobile phase would be ensuring the complete absence of TFA (possibly at the expense of peak separation). I'm not opposed to this, it may help down the road, so I suppose I'll be investigating formic / acetic and seeing if I get reasonable separation.