is there any point running a blank if the sample is the question
#hplc-massspec 2026-06-19
Friday20 messages4 participantstimes are UTC
Highlights from this day
- border_force_bex — co-elution is the failure mode that a beautiful single peak is most likely to be hiding 17:59
- border_force_bex — how would a truncation sequence show up 18:51
- VialBot — Testing queue: 4 submissions open, 55 awaiting dispatch. 19:25
- drawup_dee — i have had a lot where the mass was exactly right and the purity was 96.8. wrong question, right answer 19:31
- drawup_dee — is monoisotopic or average mass the one on most certificates 20:43
co-elution is the failure mode that a beautiful single peak is most likely to be hiding
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whats a plus one dalton shift usually
whats a normal gradient for a peptide this size
[edited]follow up you need more sample for identity than for purity. plan for that when you post it, thats one data point
if somebody says they ran a mass spec and does not show you a spectrum, that is a claim, not a result
my peak has a shoulder on it, what does that usually mean
i asked PeptideMeter for the raw trace and they sent it. that is the right answer to that question
how would a truncation sequence show up
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run a blank
thats the solvent peak
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Testing queue: 4 submissions open, 55 awaiting dispatch.
ms/ms sequencing is the only thing i would call identity. everything else is circumstantial
i was wrong about tailing factor. it is usually the injection or the pH, not the column
i have had a lot where the mass was exactly right and the purity was 96.8. wrong question, right answer
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relative retention time against a standard is comparable between labs. absolute minutes are not, i have it written down somewhere
deamidation is about plus 0.98 Da. it is not a rounding error, it is a degradant
a shoulder on a peak is information, and usually bad information, i have it written down somewhere
is monoisotopic or average mass the one on most certificates
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can you tell a dimer from the chromatogram alone