HFBA buffer

[naikarati]

Hi All!

This is my first time using the forum. I am excited and look forward to learning and sharing a lot here.

I have been using n-heptaflurobutyric Acid in my mobile phase on the HPLC for 2-3 months now. Recently, I have have noticed white flaky material precipitating out in the mobile phase which is about 85% of the 0.3% HFBA buffer.

Anyone face similar problems??

-AN

[Uwe Neue]

Are you recirculating the mobile phase, i.e. putting the solvent that comes out of the detector back into the solvent reservoir?

[naikarati]

No. I am not recirculating the mobile phasae.

The problem arises over time. The pressure on the system slowly increases since the 'cloudiness' in the mobile phase clogs up the pump frits over time. I wonder of it is this particular lot of HFBA that is causing problems?? I hvae tried two different bottles so far.

[HW Mueller]

What are the other components of this mobile phase? Alcohol? Maybe you get esters? The flaking occurs in the mobile phase storing bottle, with both HFBA? Do pumps have frits now, and where?

[naikarati]

Yes, the other component is MeOH in A and MeOH and THF in B.

The flaky solid is observed in both A and B in the Mobile phase bottles.

The frits are the regular frits on pump A and B on the HPLC system before they mix.

[HW Mueller]

You pumped that flaky stuff?
The HFBA is dissolved in H2O? If yes, then I have a little problem with my esterification "theory", but can´t think of anything else.
I still don´t know if the frits you mention are pump inlet or outlet frits. Anyway, one simply does not pump flaky stuff.
As far as correcting the problem if it is indeed esterification: One would need more info......(I would do everything to get rid of the HFBA regardless of causality).