Adding the numbers, since they settle part of this. The four things to check on any report, in order: does it name your batch, who commissioned it, what method was used, and does it report content as well as purity. A report failing any of those is weak evidence regardless of the percentage on it.
If somebody has the primary source to hand I would rather cite it than paraphrase it.
A narrower follow-up, since the general answer is now clear:
What a vetting checklist should actually contain, as opposed to a list of things that are easy to fake?
NicoleRaleigh said:The four things to check on any report, in order: does it name your batch, who commissioned it, what method was used, and does it report content as…
There is a second half to this that has not been said yet. The provenance questions are more useful than the numbers. Does the report name the batch on your vial. Is the date consistent with when that batch existed. Is it addressed to the vendor or to the person who paid for the test. Was the sample taken from general stock or supplied by the vendor. A perfect certificate for a different batch is worth nothing, and vendor-supplied samples are the most common way a genuine report ends up misleading.
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Shop Reference StandardsClosing the loop on my own question.
Went back through my own correspondence with an earlier supplier and the warning signs were all there in the replies, weeks before the quality changed. I was reading the product and not the behaviour.
PharmD_Rodriguez said:The provenance questions are more useful than the numbers.
Agreed, with a caveat about community reputation: it is a lagging indicator. Reports arrive weeks after orders, so a supplier can look excellent for a month after quality has already changed.