Hello! After deconvolution of intact mAb mass spectrum I saw a mass difference between peaks about 113 Da. The mass of the smallest sugar residue, fucose, is about 164 Da. Can anyone explain what means this mass difference?
Looks like you might have a TFA (CF3COO, m/z = 113amu) ester or adduct.
Dear Maksim,
Protonated uracil has a mass of 113. Uracil has a mass of 112.
I do not know if this can be related to the pattern you observe.
Rafik
Looks like you might have a TFA (CF3COO, m/z = 113amu) ester or adduct.
Hi Maksim
If you are using ESI based MS instruments try to avoid TFA (Ion pairing agent), as they are known to form adducts. The mass increment of 113 might actually correspond to TFA adduct. Try to acquire the MS spectrum using different ion pairing agents such as Formic acid, acetic acid etc...
I remember hydroxyproline also leads to mass increment of 113...
All the best
Hi Maksim,
113 is also a mass difference for amino acids Leucine/Isoleucine. Is it possible that you have two species, one with and without an additional Leucine/Isoleucine?
Best,
Hediye.
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