can you tell a dimer from the chromatogram alone
#hplc-massspec 2025-03-16
Sunday10 messages3 participantstimes are UTC
Highlights from this day
- HPLC_Hank — deamidation is about plus 0.98 Da. it is not a rounding error, it is a degradant, ask me again in a month 23:20
- HPLC_Hank — i have had a lot where the mass was exactly right and the purity was 96.8. wrong question, right answer, still working it out 23:21
- LC_MS_Lena — the honest position is that hobby-level interpretation of a chromatogram is worth something but not much 23:23
- LC_MS_Lena — 214nm sees the amide backbone so it sees everything. 280 only sees aromatics, ask me again in a month 23:40
- LC_MS_Lena — you need more sample for identity than for purity. plan for that when you post it 23:42
nobody runs enough blanks, including me
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deamidation is about plus 0.98 Da. it is not a rounding error, it is a degradant, ask me again in a month
i have had a lot where the mass was exactly right and the purity was 96.8. wrong question, right answer, still working it out
monoisotopic and average diverge more the bigger the molecule. say which one you are quoting
the honest position is that hobby-level interpretation of a chromatogram is worth something but not much
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do you trust an area percent from a shallow gradient
214nm sees the amide backbone so it sees everything. 280 only sees aromatics, ask me again in a month
you need more sample for identity than for purity. plan for that when you post it
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i was wrong about tailing factor. it is usually the injection or the pH, not the column