[Lab] split one vial across VendorInvestigate and PeptideMeter — 97.2% and 96.8%
split one vial across VendorInvestigate and PeptideMeter — 97.2% and 96.8%. One vial, one service, one member paying, which is the only kind of result this board should treat as evidence. Hard numbers: 97.2% and 96.8%. Anything softer than that is flagged as an impression. Spent four months confusing area% and mass%…
Started keeping a folder of every certificate I have been sent. The ones that itemise impurities are a small group and they are mostly the same suppliers.
This. Area percent answers "what fraction of what the detector saw was the peak I wanted", and people read it as "how much peptide is in the vial".
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a total of 0.4% tells you less than four named impurities adding to 0.6%
redact your own name, never the batch details
ask for the storage condition the stability statement was written against
Is water content on the document? It changes your concentration arithmetic.
HPLC-UV and LC-MS answer different questions
identity and quantity are two questions and most documents answer one
identity and quantity are two questions and most documents answer one
Adding the bit that always gets missed: the lot on the vial has to match the lot on the page, or none of this applies to your material.
Yes. The structure of the document matters at least as much as the number printed on it.
Yes.
marisol_frisk has the distinction right — one is a fraction of the detector signal, the other is a fraction of the mass.
Careful — "the metadata looks odd" is a reason to ask a question, not a conclusion. Re-issues are ordinary.
The PDF creation date being later than the analysis date is usually a re-issue or a re-export. It is worth one question and it is not evidence of anything on its own.
Yes — and the reason to ask for the whole page is that the interesting parts are the ones people crop out to fit a screenshot.