if you only read one line on a certificate, read the lot number. if you read two, read the assay
#coa-reading 2026-05-27
Wednesday16 messages3 participantstimes are UTC
Highlights from this day
- monoisotopic — the certificate from QSC is the one i use to teach this because it actually has a populated impurity table 18:41
- monoisotopic — sorry to jump in i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does 18:42
- marrow.mod — i keep every certificate in a dated folder and compare them. two suppliers had not changed their template since 2019 19:04
- marrow.mod — no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration, for what its worth 19:12
a certificate should name the method, the instrument, the column and the operator. most name none of those
the related substances table is the interesting part. a row of "not detected" means they did not look hard
water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it
the three way match is vial, certificate, invoice. if all three agree you have something
not detected means nothing
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the certificate from QSC is the one i use to teach this because it actually has a populated impurity table
sorry to jump in i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does
19:02marrow.mod pinned a message
i keep every certificate in a dated folder and compare them. two suppliers had not changed their template since 2019
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no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration, for what its worth
[edited]is water content normally on a certificate or do you have to ask
if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not
no lot no certificate
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update from 24 months ago: started asking every supplier for water content and about half now include it
whats the related substances table actually telling me