relative retention time against a standard is comparable between labs

retention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily

asked for the blank, so column age moves retention times slowly and predictably, which is why a lab compares against its own standard on the day, the axes would settle it

a charge state envelope is the same molecule carrying different numbers of protons. deconvolute and you get one mass, integration is a judgement call

retention time is a hint. identity comes from the mass, and preferably from fragmentation as well, deconvoluted, obviously

column age moves retention time and does not usually move the area percent much, ask for the blank

looking at a spectrum now i asked PeptideMeter for the raw trace and they sent it. that is the right answer to that question, at 214 anyway

if you post a trace, post the axes. a chromatogram without a time axis is a shape, verify it before you rely on it

shallow gradient

a two point gap between labs is entirely explicable by a different gradient and a different column age, check the axes first

a deletion sequence shows up as a mass short by exactly one residue, which is why the mass is worth reading, identity needs the mass

nothing about a good chromatogram makes research use only material approved for human use

disagree but ok, area percent not mass