By HW Mueller on Thursday, March 27, 2003 - 12:06 am:
This problem has been mentioned before, in other chains. Since neither lit. searches, communications with the manufacturer, nor other contacts have gotten anywhere it seems appropriate to start a separate chain on this.
We have seen a permanent change in the resolution of a Mab and its Fab fragment (MW ~150000 and 100000) after using TFA or its butiric acid analog (HFBA) in the mobile phase.
The question is, once more: Has anybody seen this?
Also, in view of the chains "LC-MS: Problems with perfluorinated acids in mobile phase", January 2;
"Equivalency of column test procedures", January 27;
and "Shifting baseline after first analyte", March 20:
Has anybody else seen any study on the interaction (reaction?) of ion pairing agents with silica gel (IR, Raman, NMR, or just performance changes)? Now, I am aware of the many warnings, especially to limit a column to ion pair use, but: Is there any unequivocal evidence (besides the mentioned material)? Has anybody looked into what is going on? For instance, does TFA form ester bonds with Si-OH??
By HW Mueller on Thursday, March 27, 2003 - 12:46 am:
Sorry, I forgot to mention that the resolution improved somewhat, SLOWLY, when an ideal mobile phase (PBS) was used after the ~1% TFA..... This PARTIAL improvement seems to indicate that the deterioration was not caused by the acidity.
Propanol in the mobile phase also caused a downgrading of the resolution, but this was ~ reversible.