[PSA] batch is not what most of this community thinks it is
batch is not what most of this community thinks it is. It comes up every few weeks and the answer has not changed. The document I was worried about turned out to be a re-issue with a later creation date. Asked, got the original, entirely ordinary. Asked for the storage condition behind the stability statement. Got it…
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.
What does the method line actually say? Not the technique — the column and the gradient.
the related substances line is where the story is
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".
Pushing back a little: a missing field is usually presentation, not concealment. Ask for the full document before drawing conclusions.
axis labels included, always
redact your own name, never the batch details
redact your own name, never the batch details
gallbladder_gary has the distinction right — one is a fraction of the detector signal, the other is a fraction of the mass.
HPLC-UV and LC-MS answer different questions