analytically speaking column age moves retention time and does not usually move the area percent much, the summary already judged it
Thread · #hplc-massspec · 2025-10-17
anyone got a sense of typical run times on these methods
Spun off from a message in #hplc-massspec on 2025-10-17. 14 messages, 4 participants.
The message this came from
- LC_MS_Lena — anyone got a sense of typical run times on these methods — and what would you want to see before accepting an identity claim 17:35
that spectrum was sample prep retention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily, carryover is the cheap explanation
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a purity number is a method result. change the method and you change the number, honestly and legitimately
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integration difference
[edited]what gradient are people actually seeing on these certificates
retention time is a hint. identity comes from the mass, and preferably from fragmentation as well, retention time is only a hint
looking at a spectrum now if you post a trace, post the axes. a chromatogram without a time axis is a shape, carryover is the cheap explanation
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i would want a mass, a fragmentation pattern and a chromatogram before i called something identified
the retention time on its own means nothing across two labs. the relative order of the peaks means quite a lot, the summary already judged it
counterpoint a two point gap between labs is entirely explicable by a different gradient and a different column age
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ask for the gradient
i have a number at about a third of what i expected, is that a charge state
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baseline resolved means the trace comes back down between the peaks. if it does not, the integration is a judgement call, one persons experience
a deletion sequence shows up as a mass short by exactly one residue, which is why the mass is worth reading