the certificate from SGN is the one i use to teach this because it actually has a populated impurity table
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#coa-reading 2025-07-21
Monday27 messages5 participantstimes are UTC
Highlights from this day
- travel_cooler — the certificate from SGN is the one i use to teach this because it actually has a populated impurity table 00:48
- travel_cooler — net peptide is gross mass minus water minus counterion. that is why 11.4mg of powder can be a correct 10mg vial 00:57
- travel_cooler — a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists 01:47
- travel_cooler — update on the earlier thing nobody can authenticate a certificate from a scan. you authenticate the material by testing it yourself sterility and endotoxin are… 01:59
- VialBot — Purity check: no report on file for lot F-1330. Nothing logged either way. 02:49
is sterility tested as part of a normal purity certificate
thats a real table
residual solvents matter more than people think for anything that went through a lot of purification steps
sloppy not sinister
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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is endotoxin ever tested on research material
water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it
is there a standard layout or does every lab do their own
test it yourself
thats the counterion
good certificate actually
a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists
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tfa or acetate, how do i tell from the paperwork
net not gross
while im here the font on this one changes halfway down, am i being paranoid
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a certificate should name the method, the instrument, the column and the operator. most name none of those
i keep every certificate in a dated folder and compare them. two suppliers had not changed their template since 2019, thats one data point
update on the earlier thing nobody can authenticate a certificate from a scan. you authenticate the material by testing it yourself
sterility and endotoxin are separate tests and almost nobody runs either on research material
ask for water content
coming back after 26 months, has the pinned reading guide changed
whats the related substances table actually telling me
i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does
tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance
Purity check: no report on file for lot F-1330. Nothing logged either way.
is water content normally on a certificate or do you have to ask
weigh the vial