is water content normally on a certificate or do you have to ask
#coa-reading 2026-01-16
Friday31 messages8 participantstimes are UTC
Highlights from this day
- protein_floor — a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists 20:57
- protein_floor — does anyone keep a folder of certificates to compare over time 21:18
- VialBot — Channel stats, last 30 days: 110 messages from 61 members. 22:41
- VialBot — New independent result logged — ERP, lot H-2814, purity 98.6% (Medutest). 23:18
check the lot
💀11⚠️14
two certificates from the same supplier have an identical chromatogram, is that normal
a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists
sloppy not sinister
no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration
should a certificate say which instrument and method they used
does anyone actually check the residual solvents section
water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it, ymmv
good certificate actually
does anyone keep a folder of certificates to compare over time
✅3🎉12
is there a standard layout or does every lab do their own
coming back after 7 months, has the pinned reading guide changed
i keep every certificate in a dated folder and compare them. two suppliers had not changed their template since 2019
whats the related substances table actually telling me
*VendorInvestigate not the other one
net peptide is gross mass minus water minus counterion. that is why 11.4mg of powder can be a correct 10mg vial
thats a real table
[edited]sorry to jump in if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not
not detected means nothing
thats a tell
sterility and endotoxin are separate tests and almost nobody runs either on research material
no lot no certificate
net not gross
one decimal versus two is usually just house style, not precision
Channel stats, last 30 days: 110 messages from 61 members.
update from 3 months ago: started asking every supplier for water content and about half now include it
the related substances table is the interesting part. a row of "not detected" means they did not look hard
test it yourself
thats the counterion
😂13
New independent result logged — ERP, lot H-2814, purity 98.6% (Medutest).