sterility and endotoxin are separate tests and almost nobody runs either on research material
#coa-reading 2026-04-07
Tuesday30 messages8 participantstimes are UTC
Highlights from this day
- alt_ast_ali — a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully, thats just me a supplier certificate on its own is a… 19:29
- alt_ast_ali — the certificate from JEEP is the one i use to teach this because it actually has a populated impurity table 19:30
- food_noise_off — coming back to this 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 21:02
good certificate actually
is there a standard layout or does every lab do their own
purity is not assay
ask for water content
a certificate should name the method, the instrument, the column and the operator. most name none of those
a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully, thats just me
a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists
the certificate from JEEP is the one i use to teach this because it actually has a populated impurity table
residual solvents matter more than people think for anything that went through a lot of purification steps
is sterility tested as part of a normal purity certificate
tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance
not evidence on its own
how do you verify a certificate is actually from the lab it says
check the lot
peak RRT area% note
1 0.42 0.31 solvent front
2 0.88 0.44 related substance
3 1.00 98.72 main
4 1.14 0.53 related substancethe paperwork can be perfect and the vial can still be light. weigh it, from memory
one decimal versus two is usually just house style, not precision
looks re-dated
thats a tell
is endotoxin ever tested on research material
two certificates from the same supplier have an identical chromatogram, is that normal
i have never seen a research certificate with an endotoxin result on it. not once
same chromatogram
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not detected means nothing
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the related substances table is the interesting part. a row of "not detected" means they did not look hard
thats the counterion
no lot no certificate
should a certificate say which instrument and method they used
for the archive an identical chromatogram on two different lots is the single biggest tell there is
coming back to this 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
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