[Discussion] we are measuring purity at the wrong time and calling it noise
we are measuring purity at the wrong time and calling it noise. Change my mind, genuinely — I have no stake in being right about this. How to ask for a batch record without it turning into a negotiation. One email, three requests: the batch-specific certificate for lot X, the method line behind it, and the storage…
a certificate with no method line is decorative
Right, and net peptide content is where the counterion and the water go. Both numbers can be honest and very different.
Are the related substances itemised or is it a single total?
Did you get the chromatogram or only the summary line?
area% is not mass%, and the difference is the whole game
Not quite. Two labs with different gradients can resolve a close-eluting impurity differently and both be reporting honestly.
The document I was worried about turned out to be a re-issue with a later creation date. Asked, got the original, entirely ordinary.
Pushing back a little: a missing field is usually presentation, not concealment. Ask for the full document before drawing conclusions.