good certificate actually
#coa-reading 2026-05-04
Monday30 messages9 participantstimes are UTC
Highlights from this day
- evidence_or_not — for the archive tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance 20:14
- customs_owl — my 20mg vial weighed more than 10mg of powder, is the certificate lying 21:44
- VialBot — New independent result logged — QYB, lot F-1330, purity 99.2% (Janoshik). 21:50
update on the earlier thing the honest summary is that a certificate tells you what the supplier says about a lot they chose to test
check the lot
i have never seen a research certificate with an endotoxin result on it. not once
water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it
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
is area percent the same thing as how many mg are in the vial
a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists
looks re-dated
for the archive tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance
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the three way match is vial, certificate, invoice. if all three agree you have something
i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does
does purity by hplc at one wavelength miss things
the font on this one changes halfway down, am i being paranoid
slightly off topic but is endotoxin ever tested on research material
one decimal versus two is usually just house style, not precision, for what its worth
a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists
should a certificate say which instrument and method they used
residual solvents matter more than people think for anything that went through a lot of purification steps
what does net peptide content mean next to gross mass
test it yourself
why would a vial be 99 pure and still assay under label
the paperwork can be perfect and the vial can still be light. weigh it
thats a real table
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single wavelength detection can miss a co-eluting impurity that does not absorb there
my 20mg vial weighed more than 10mg of powder, is the certificate lying
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i asked SWB for the method and they sent it. that alone put them ahead of most
sterility and endotoxin are separate tests and almost nobody runs either on research material, i have it written down somewhere
New independent result logged — QYB, lot F-1330, purity 99.2% (Janoshik).
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i keep every certificate in a dated folder and compare them. two suppliers had not changed their template since 2019
does anyone actually check the residual solvents section