a dimer usually shows up late and at roughly double the mass. the chromatogram alone will not tell you
#hplc-massspec 2026-05-09
Saturday15 messages5 participantstimes are UTC
Highlights from this day
- pinch_not_stretch — a dimer usually shows up late and at roughly double the mass. the chromatogram alone will not tell you 15:27
- pinch_not_stretch — is a tailing factor of anything specific a problem 16:29
- madrid_mg — if somebody says they ran a mass spec and does not show you a spectrum, that is a claim, not a result, thats one data point 16:30
- coelution_cai — baseline drift on a gradient is normal. baseline drift on an isocratic hold is your column 16:44
- pinch_not_stretch — ms/ms sequencing is the only thing i would call identity. everything else is circumstantial 19:45
integration difference
thats a charge state
does ms/ms actually prove identity or just make it very likely
is a tailing factor of anything specific a problem
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pinch_not_stretcha dimer usually shows up late and at roughly double the mass. the chromatogram alone…
if somebody says they ran a mass spec and does not show you a spectrum, that is a claim, not a result, thats one data point
a shoulder on a peak is information, and usually bad information
does retention time on its own tell you what the compound is
shallow gradient
whats a normal gradient for a peptide this size
baseline drift on a gradient is normal. baseline drift on an isocratic hold is your column
oxidation is about plus 15.99 Da and is usually methionine or tryptophan
right so how do you spot a deletion in a sequence from mass alone
quick one semaglutide is about 4113.6 Da. [M+2H]2+ lands near 2057.8, [M+3H]3+ near 1372.2
ms/ms sequencing is the only thing i would call identity. everything else is circumstantial