thats the solvent peak
#hplc-massspec 2025-08-26
Tuesday18 messages5 participantstimes are UTC
Highlights from this day
- area_percent — two labs a point or two apart on the same lot is normal and gets mistaken for one of them being wrong constantly 14:35
- HPLC_Hank — ms/ms sequencing is the only thing i would call identity. everything else is circumstantial 14:56
- area_percent — update from 20 months ago: switched to asking for the chromatogram rather than the number and it changed everything 15:05
- area_percent — i asked PeptideMeter for the raw trace and they sent it. that is the right answer to that question, n of 1 obviously 15:07
run a blank
show me the spectrum
*VendorInvestigate not the other one
two labs a point or two apart on the same lot is normal and gets mistaken for one of them being wrong constantly
does retention time on its own tell you what the compound is
plus 0.98 is deamidation
a warm transit can put a visible degradant peak on a chromatogram. that is what 21 days at ambient does
ms/ms sequencing is the only thing i would call identity. everything else is circumstantial
👍5❤️4
is monoisotopic or average mass the one on most certificates
update from 20 months ago: switched to asking for the chromatogram rather than the number and it changed everything
[edited]214nm sees the amide backbone so it sees everything. 280 only sees aromatics, for what its worth
i asked PeptideMeter for the raw trace and they sent it. that is the right answer to that question, n of 1 obviously
integration difference
💀4
how would a truncation sequence show up
retention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily
shallow gradient
if the lab reports area percent without stating the wavelength, the number is less useful than it looks