thats a real table
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 / 10mg🔥13❤️13🎉3
#coa-reading 2026-01-03
Saturday30 messages7 participantstimes are UTC
Highlights from this day
- vat_on_import — slightly off topic but the honest summary is that a certificate tells you what the supplier says about a lot they chose to test 18:01
- cat_on_the_tray — what does net peptide content mean next to gross mass 18:45
- tail_factor — the certificate from FGP is the one i use to teach this because it actually has a populated impurity table 20:37
- VialBot — Batch lookup SG-1177: 4 independent reports on file, earliest 2025-08-15. 20:49
- cat_on_the_tray — the paperwork can be perfect and the vial can still be light. weigh it 21:30
single wavelength detection can miss a co-eluting impurity that does not absorb there
slightly off topic but the honest summary is that a certificate tells you what the supplier says about a lot they chose to test
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update from 25 months ago: started asking every supplier for water content and about half now include it, anyway
the related substances table is the interesting part. a row of "not detected" means they did not look hard, still working it out
no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration
sorry to jump in is endotoxin ever tested on research material
sterility and endotoxin are separate tests and almost nobody runs either on research material
is sterility tested as part of a normal purity certificate
slightly off topic but gross mass on a jewellery scale plus the water content is enough to catch most underfills
how do you verify a certificate is actually from the lab it says
what does net peptide content mean next to gross mass
weights-monthly.csv
861 rows · not retained in the public archive
unrelated but tfa or acetate, how do i tell from the paperwork
mixed fonts and inconsistent kerning in one document is worth a second look
purity is what fraction of the contents is the target. assay is how many mg are actually there. different questions
[edited]*VendorInvestigate not the other one
while im here whats the related substances table actually telling me
my 30mg vial weighed more than 20mg of powder, is the certificate lying
not evidence on its own
water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it, not advice obviously
test it yourself
[edited]looks re-dated
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thats a tell
| 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 |
the certificate from FGP is the one i use to teach this because it actually has a populated impurity table
quick one why would a vial be 99 pure and still assay under label
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Batch lookup SG-1177: 4 independent reports on file, earliest 2025-08-15.
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residual solvents matter more than people think for anything that went through a lot of purification steps
the paperwork can be perfect and the vial can still be light. weigh it
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purity is not assay