for the archive the three way match is vial, certificate, invoice. if all three agree you have something
#coa-reading 2026-06-06
Saturday30 messages7 participantstimes are UTC
Highlights from this day
- VialBot — Verification log updated: HJ — evidence added, status unchanged. 19:48
- fasting_insulin — tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance 20:17
- fasting_insulin — a vial can be 99.4% pure and hold 8.1mg of a 10mg label. both numbers are true and only one of them is the one you care about, we shall see 21:34
- fasting_insulin — for the archive is endotoxin ever tested on research material 21:46
- evidence_or_not — ok so residual solvents matter more than people think for anything that went through a lot of purification steps 22:07
is sterility tested as part of a normal purity certificate
Verification log updated: HJ — evidence added, status unchanged.
the paperwork can be perfect and the vial can still be light. weigh it
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good certificate actually
mixed fonts and inconsistent kerning in one document is worth a second look
tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance
net not gross
tfa or acetate, how do i tell from the paperwork
update on the earlier thing certificate is dated before the lot date, is that just sloppiness
single wavelength detection can miss a co-eluting impurity that does not absorb there
a certificate should name the method, the instrument, the column and the operator. most name none of those
not detected means nothing
tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance
| Line | Claims | Does not claim |
|---|---|---|
| Purity (area %) | fraction of detected material that is the target | how many mg are in the vial |
| Assay / content | mg of target per vial | that it is sterile |
| Water content | mass fraction that is water | anything about purity |
| Counterion | salt form and its mass share | net peptide unless stated |
| Related substances | what else was seen | what was not looked for |
does anyone keep a folder of certificates to compare over time
On this day 8 years ago this channel logged 60 messages.
nobody can authenticate a certificate from a scan. you authenticate the material by testing it yourself
Reminder set. I will post here in 5 days.
is area percent the same thing as how many mg are in the vial
if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not
a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists, anyway
weigh the vial
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thats the counterion
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a vial can be 99.4% pure and hold 8.1mg of a 10mg label. both numbers are true and only one of them is the one you care about, we shall see
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the certificate from GGPeps is the one i use to teach this because it actually has a populated impurity table, i could be wrong
for the archive is endotoxin ever tested on research material
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thats a real table
ask for water content
ok so residual solvents matter more than people think for anything that went through a lot of purification steps
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same chromatogram
test it yourself
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