sterility and endotoxin are separate tests and almost nobody runs either on research material, i could be wrong
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#coa-reading 2026-05-19
Tuesday26 messages7 participantstimes are UTC
Highlights from this day
- bpc_sceptic — sterility and endotoxin are separate tests and almost nobody runs either on research material, i could be wrong 20:28
- no_escrow_nate — i asked JEEP for the method and they sent it. that alone put them ahead of most 20:52
- sunday_shot — an identical chromatogram on two different lots is the single biggest tell there is, ask me again in a month 22:19
good certificate actually
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is water content normally on a certificate or do you have to ask
unrelated but 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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i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does, n of 1 obviously
i asked JEEP for the method and they sent it. that alone put them ahead of most
residual solvents matter more than people think for anything that went through a lot of purification steps
purity is what fraction of the contents is the target. assay is how many mg are actually there. different questions
purity is not assay
not detected means nothing
my 30mg vial weighed more than 5mg of powder, is the certificate lying
should a certificate say which instrument and method they used
ask for water content
not evidence on its own
does purity by hplc at one wavelength miss things
purity is what fraction of the contents is the target. assay is how many mg are actually there. different questions
is endotoxin ever tested on research material
is there a standard layout or does every lab do their own
a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists, i think
a certificate should name the method, the instrument, the column and the operator. most name none of those
whats the minimum a certificate has to have before you take it seriously
retention time shifts between runs are normal. relative retention time is the number to compare
an identical chromatogram on two different lots is the single biggest tell there is, ask me again in a month
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check the lot
is a supplier certificate worth anything on its own
follow up the related substances table is the interesting part. a row of "not detected" means they did not look hard, i have it written down somewhere
does anyone keep a folder of certificates to compare over time