By Kom on Wednesday, March 10, 2004 - 08:45 am:
How to explain that TFA causes ion suppression in LC/MS, but not other acids such as formic acid. What is the really meaning of ion suppression in this area?
By Anonymous on Monday, March 15, 2004 - 12:54 am:
Hi, Kom
TriFluoroacetic Acid is claimed to form ion pairs with basic analytes. The formation of couple [base-TFA] is in competition with the formation of pseudomolecular ion of analyte [base+H]+ and so you can observe ion suppression (of pseudomolecular ion) in an electrospray ionization interface for LC/MS.
Note that this is not an absolute rule; ion suppression of TFA is probably analyte dependent and/or at very low concentration (<1 mM) it is possible to use TFA with good results in an ESI source.
Following a method outlined by Di Corcia et al. I have obtained good results for herbicide residues analysis in water with TFA 10 µM in mobile phase.
By Kom on Tuesday, March 16, 2004 - 01:21 pm: