how do you spot a deletion in a sequence from mass alone
#hplc-massspec 2025-05-03
Saturday16 messages5 participantstimes are UTC
Highlights from this day
- slow.taper — two labs a point or two apart on the same lot is normal and gets mistaken for one of them being wrong constantly 14:38
- provincial_pat — truncations show as a mass deficit matching one or more residues. you need the sequence to say which 15:06
- apnoea_down_two — if the number you are staring at is a third of what you expected, do the charge state arithmetic before you panic, n of 1 obviously 15:56
two labs a point or two apart on the same lot is normal and gets mistaken for one of them being wrong constantly
🙏1
within inter-lab range
truncations show as a mass deficit matching one or more residues. you need the sequence to say which
run a blank
you need more sample for identity than for purity. plan for that when you post it
nobody runs enough blanks, including me
if the number you are staring at is a third of what you expected, do the charge state arithmetic before you panic, n of 1 obviously
whats the void volume peak, is that always solvent
shallow gradient
do you trust an area percent from a shallow gradient
do the arithmetic
co-elution is the failure mode that a beautiful single peak is most likely to be hiding
ms/ms sequencing is the only thing i would call identity. everything else is circumstantial
plus 16 is oxidation
oxidation is about plus 15.99 Da and is usually methionine or tryptophan