unpopular opinion: most of what gets said here about certificate of analysis is guesswork
unpopular opinion: most of what gets said here about certificate of analysis is guesswork — a position I have arrived at slowly and would like tested. LC-MS gives you identity; UV purity gives you a relative quantity. A document with the first and not the second, or the reverse, is answering half the question. Asked…
Ask what the stability statement was written against — temperature, light, and whether it was the lyophilised powder or the reconstituted solution. Those are three different claims.
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That is the catalogue certificate rather than the batch-specific one. Same layout, completely different status.
net peptide content and purity are two different numbers on the same vial
ask for the storage condition the stability statement was written against
Did you get the chromatogram or only the summary line?
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.
area% is not mass%, and the difference is the whole game
Is water content on the document? It changes your concentration arithmetic.
the related substances line is where the story is