if you only read one line on a certificate, read the lot number. if you read two, read the assay
#coa-reading 2026-02-25
Wednesday38 messages9 participantstimes are UTC
Highlights from this day
- nordic_price_nils — no lot number on this certificate, does that make it worthless 11:30
- VialBot — New independent result logged — GL Biochem, lot D-0718, purity 96.8% (PeptideMeter). 14:08
- reship_rita — no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration 17:11
- assay_not_purity — is sterility tested as part of a normal purity certificate 19:03
*VendorInvestigate not the other one
thats a tell
no lot no certificate
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no lot number on this certificate, does that make it worthless
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weigh the vial
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retention time shifts between runs are normal. relative retention time is the number to compare
an identical chromatogram on two different lots is the single biggest tell there is
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i have never seen a research certificate with an endotoxin result on it. not once
update from 26 months ago: started asking every supplier for water content and about half now include it, happy to be corrected
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thats a real table
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sterility and endotoxin are separate tests and almost nobody runs either on research material
residual solvents matter more than people think for anything that went through a lot of purification steps
check the lot
the retention time on this one is different from the last lot, problem
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not detected means nothing
looks re-dated
how do you verify a certificate is actually from the lab it says
nordic_price_nilsretention time shifts between runs are normal. relative retention time is the number…
does anyone keep a folder of certificates to compare over time
is a supplier certificate worth anything on its own
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is water content normally on a certificate or do you have to ask
nobody can authenticate a certificate from a scan. you authenticate the material by testing it yourself
New independent result logged — GL Biochem, lot D-0718, purity 96.8% (PeptideMeter).
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sloppy not sinister
whats the related substances table actually telling me
a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists
my 40mg vial weighed more than 5mg of powder, is the certificate lying
should a certificate say which instrument and method they used
gross mass on a jewellery scale plus the water content is enough to catch most underfills
nobody can authenticate a certificate from a scan. you authenticate the material by testing it yourself
does purity by hplc at one wavelength miss things
certificate is dated before the lot date, is that just sloppiness
no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration
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right so the honest summary is that a certificate tells you what the supplier says about a lot they chose to test
a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully
two certificates from the same supplier have an identical chromatogram, is that normal
[edited]same chromatogram
is sterility tested as part of a normal purity certificate
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good certificate actually