unrelated but mixed fonts and inconsistent kerning in one document is worth a second look, i think
#coa-reading 2025-08-16
Saturday30 messages4 participantstimes are UTC
Highlights from this day
- salt_bridge — update on the earlier thing is there a standard layout or does every lab do their own 13:27
- truncation_tru — the related substances table is the interesting part. a row of "not detected" means they did not look hard 13:52
- mhra_unlicensed — the three way match is vial, certificate, invoice. if all three agree you have something 14:09
- karl_fischer — a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists 14:55
the paperwork can be perfect and the vial can still be light. weigh it, i could be wrong
update on the earlier thing is there a standard layout or does every lab do their own
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looks re-dated
an identical chromatogram on two different lots is the single biggest tell there is, your mileage will differ
a certificate should name the method, the instrument, the column and the operator. most name none of those
*Janoshik not the other one
sorry to jump in update from 7 months ago: started asking every supplier for water content and about half now include it, ymmv
not detected means nothing
check the lot
the related substances table is the interesting part. a row of "not detected" means they did not look hard
✅10
the certificate from TFC is the one i use to teach this because it actually has a populated impurity table
for the archive i have never seen a research certificate with an endotoxin result on it. not once
update on the earlier thing is endotoxin ever tested on research material
the three way match is vial, certificate, invoice. if all three agree you have something
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net peptide is gross mass minus water minus counterion. that is why 11.4mg of powder can be a correct 10mg vial
does purity by hplc at one wavelength miss things
two certificates from the same supplier have an identical chromatogram, is that normal
😂4
single wavelength detection can miss a co-eluting impurity that does not absorb there
whats the related substances table actually telling me
one decimal versus two is usually just house style, not precision
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does anyone actually check the residual solvents section
no lot number on this certificate, does that make it worthless
good certificate actually
i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does, take that with a pinch of salt
a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists
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gross mass on a jewellery scale plus the water content is enough to catch most underfills
i keep every certificate in a dated folder and compare them. two suppliers had not changed their template since 2019
✅5
what does net peptide content mean next to gross mass
sloppy not sinister