[PSA] purity is not what most of this community thinks it is
purity is not what most of this community thinks it is. Two minutes of reading now saves an argument later. My first certificate had a compound name, a percentage and a logo. I thought that was normal. It is not, and now I know what to ask for. How to ask for a batch record without it turning into a negotiation. One…
Left up and flaired Explainer. This is the answer we keep linking, written properly.
Not quite. Two labs with different gradients can resolve a close-eluting impurity differently and both be reporting honestly.
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.
Pushing back a little: a missing field is usually presentation, not concealment. Ask for the full document before drawing conclusions.
That is the catalogue certificate rather than the batch-specific one. Same layout, completely different status.
Yes. The structure of the document matters at least as much as the number printed on it.
Correction: that is net peptide content, not purity. Different number, different meaning, and the document says so if you read the row label.
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.