does purity actually matter or is it forum lore at this point
does purity actually matter or is it forum lore at this point. Searched first, found three threads that contradict each other, hence the post. Asked QST for the batch-specific certificate and had the full document — batch, date, method line naming the column — inside six hours. That is now my baseline for everybody.…
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.
the related substances line is where the story is
the lot on the vial has to match the lot on the page
Yes — and the reason to ask for the whole page is that the interesting parts are the ones people crop out to fit a screenshot.
The four things a certificate must carry, and what each one is for.
Batch identifier ties the document to your vial; without it the document is about somebody else’s material. Date of analysis tells you when the number was true. Method — column, gradient, wavelength — is what makes the figure reproducible rather than asserted. Individual related substances give you the shape of what else is in there.
Everything beyond those four is welcome. Anything missing from them is a question to ask before you order, and in my experience the answer arrives quickly from the suppliers who have a batch record to draw it from.