oxidation is about plus 15.99 Da and is usually methionine or tryptophan
#hplc-massspec 2026-01-07
Wednesday14 messages5 participantstimes are UTC
Highlights from this day
- noct.titrate — you need more sample for identity than for purity. plan for that when you post it 18:39
- low_and_slow — retention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily 19:19
- HPLC_Hank — semaglutide is about 4113.6 Da. [M+2H]2+ lands near 2057.8, [M+3H]3+ near 1372.2 19:22
- HPLC_Hank — if the lab reports area percent without stating the wavelength, the number is less useful than it looks 20:28
- HPLC_Hank — i have had a lot where the mass was exactly right and the purity was 96.8. wrong question, right answer 20:38
whats a plus one dalton shift usually
you need more sample for identity than for purity. plan for that when you post it
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retention time is a hint
janoshik-a-2601.pdf
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do you trust an area percent from a shallow gradient
retention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily
semaglutide is about 4113.6 Da. [M+2H]2+ lands near 2057.8, [M+3H]3+ near 1372.2
how do you spot a deletion in a sequence from mass alone
can you tell a dimer from the chromatogram alone
thats the solvent peak
if the lab reports area percent without stating the wavelength, the number is less useful than it looks
i have had a lot where the mass was exactly right and the purity was 96.8. wrong question, right answer
plus 16 is oxidation
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integration difference