ok so the honest position is that hobby-level interpretation of a chromatogram is worth something but not much
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#hplc-massspec 2026-02-01
Sunday17 messages4 participantstimes are UTC
Highlights from this day
- fern_freezes — ok so the honest position is that hobby-level interpretation of a chromatogram is worth something but not much 12:59
- ms_ms_mira — a warm transit can put a visible degradant peak on a chromatogram. that is what 6 days at ambient does 15:30
- ms_ms_mira — i asked Janoshik for the raw trace and they sent it. that is the right answer to that question 16:06
nobody runs enough blanks, including me
ms/ms or it isnt identity
run a blank
shallow gradient
deamidation is about plus 0.98 Da. it is not a rounding error, it is a degradant
do the arithmetic
oxidation is about plus 15.99 Da and is usually methionine or tryptophan
tirzepatide is about 4813.5 Da, so 2+ is near 2407.8 and 3+ near 1605.5
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show me the spectrum
plus 0.98 is deamidation
a warm transit can put a visible degradant peak on a chromatogram. that is what 6 days at ambient does
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i asked Janoshik for the raw trace and they sent it. that is the right answer to that question
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integration difference
[edited]need more sample
co-elution is the failure mode that a beautiful single peak is most likely to be hiding
how would a truncation sequence show up