check the lot
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#coa-reading 2025-06-29
Sunday23 messages6 participantstimes are UTC
Highlights from this day
- yyz_vial — is area percent the same thing as how many mg are in the vial 14:37
- luerlok — i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does 18:21
- luerlok — the related substances table is the interesting part. a row of "not detected" means they did not look hard, for what its worth 18:23
is area percent the same thing as how many mg are in the vial
lot-log.csv
761 rows · not retained in the public archive
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update on the earlier thing net peptide is gross mass minus water minus counterion. that is why 11.4mg of powder can be a correct 10mg vial
sorry to jump in i asked SWB for the method and they sent it. that alone put them ahead of most, for what its worth
residual solvents matter more than people think for anything that went through a lot of purification steps
same chromatogram
if you only read one line on a certificate, read the lot number. if you read two, read the assay
thats the counterion
no lot no certificate
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tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance
no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration
update from 20 months ago: started asking every supplier for water content and about half now include it
looks re-dated
not evidence on its own
the certificate from SWB is the one i use to teach this because it actually has a populated impurity table
certificate is dated before the lot date, is that just sloppiness
i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does
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the related substances table is the interesting part. a row of "not detected" means they did not look hard, for what its worth
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is there a standard layout or does every lab do their own
the three way match is vial, certificate, invoice. if all three agree you have something, ask me again in a month
i have never seen a research certificate with an endotoxin result on it. not once
sloppy not sinister
purity is what fraction of the contents is the target. assay is how many mg are actually there. different questions, ask me again in a month