genuine question i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does
#coa-reading 2026-04-16
Thursday14 messages3 participantstimes are UTC
Highlights from this day
- assay_not_purity — update from 15 months ago: started asking every supplier for water content and about half now include it sterility and endotoxin are separate tests and almost nobody… 20:58
- assay_not_purity — net peptide is gross mass minus water minus counterion. that is why 11.4mg of powder can be a correct 10mg vial 20:59
- assay_not_purity — the certificate from WXT is the one i use to teach this because it actually has a populated impurity table, someone check my working 21:27
update from 15 months ago: started asking every supplier for water content and about half now include it
sterility and endotoxin are separate tests and almost nobody runs either on research material
net peptide is gross mass minus water minus counterion. that is why 11.4mg of powder can be a correct 10mg vial
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good certificate actually
my 15mg vial weighed more than 30mg of powder, is the certificate lying
the certificate from WXT is the one i use to teach this because it actually has a populated impurity table, someone check my working
is water content normally on a certificate or do you have to ask
an identical chromatogram on two different lots is the single biggest tell there is
purity is what fraction of the contents is the target. assay is how many mg are actually there. different questions
purity is not assay
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sterility and endotoxin are separate tests and almost nobody runs either on research material
is a supplier certificate worth anything on its own
quick one i keep every certificate in a dated folder and compare them. two suppliers had not changed their template since 2019, not advice obviously
not detected means nothing