someone explain COA to me like I have not read a paper in years
The title is the whole question — someone explain COA to me like I have not read a paper in years — but here is why I am asking. 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. Ask what the stability…
Area percent is the peak area of your compound over the total integrated area, at one wavelength, on one gradient. It is a relative measure of what the detector saw, not a mass fraction of the vial.
Related substances itemised individually is a much stronger document than a single total, because it tells you the shape of the impurity profile rather than its size.
I would not read a rounded figure as evasive. Plenty of documents round to one decimal as house style.
Does the lot on the vial match the lot on the page?
HPLC-UV and LC-MS answer different questions
water content is on there and everyone skips it
Agreed — the itemised related substances table is the difference between a document and a receipt.
Yes. The structure of the document matters at least as much as the number printed on it.
Careful — "the metadata looks odd" is a reason to ask a question, not a conclusion. Re-issues are ordinary.
That is not what the method line says. It names the technique; it does not certify the operator.
Sent one vial to Janoshik and VendorInvestigate. 97.9% and a claimed 97.0%. Cost me more than the vial and I would do it again.
a total of 0.4% tells you less than four named impurities adding to 0.6%
post the whole document, not the headline number
the related substances line is where the story is