how do you verify a certificate is actually from the lab it says
#coa-reading 2025-06-18
Wednesday34 messages8 participantstimes are UTC
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two certificates from the same supplier have an identical chromatogram, is that normal
not detected means nothing
a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists
[edited]the three way match is vial, certificate, invoice. if all three agree you have something
[edited]thats the counterion
net not gross
whats the minimum a certificate has to have before you take it seriously
residual solvents matter more than people think for anything that went through a lot of purification steps
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thats a real table
net peptide is gross mass minus water minus counterion. that is why 11.4mg of powder can be a correct 10mg vial
purity is not assay
i asked SGN for the method and they sent it. that alone put them ahead of most
sloppy not sinister
[edited]i have never seen a research certificate with an endotoxin result on it. not once
right so the retention time on this one is different from the last lot, problem
[edited]the font on this one changes halfway down, am i being paranoid
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tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance
one decimal versus two is usually just house style, not precision
gross mass on a jewellery scale plus the water content is enough to catch most underfills
test it yourself
the certificate from SWB is the one i use to teach this because it actually has a populated impurity table
is endotoxin ever tested on research material
lot bought purity assay/label
A-2418 2025-03 99.1% 9.6 / 10mg
A-2601 2025-08 98.7% 9.8 / 10mg
B-0114 2026-01 99.3% 9.4 / 10mg
B-0329 2026-04 98.9% 9.9 / 10mgno lot number on this certificate, does that make it worthless
follow up no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration
a certificate should name the method, the instrument, the column and the operator. most name none of those
looks re-dated
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sterility and endotoxin are separate tests and almost nobody runs either on research material
[edited]water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it
i keep every certificate in a dated folder and compare them. two suppliers had not changed their template since 2019
mixed fonts and inconsistent kerning in one document is worth a second look
genuine question tfa or acetate, how do i tell from the paperwork
lot bought purity assay/label
A-2418 2025-03 99.1% 9.6 / 10mg
A-2601 2025-08 98.7% 9.8 / 10mg
B-0114 2026-01 99.3% 9.4 / 10mg
B-0329 2026-04 98.9% 9.9 / 10mgretention time shifts between runs are normal. relative retention time is the number to compare
gross mass on a jewellery scale plus the water content is enough to catch most underfills
net peptide is gross mass minus water minus counterion. that is why 11.4mg of powder can be a correct 10mg vial
if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not, ill dig out the number
thats a tell