residual solvents matter more than people think for anything that went through a lot of purification steps
#coa-reading 2025-05-29
Thursday24 messages5 participantstimes are UTC
Highlights from this day
- third_shift — ok so i asked GGPeps for the method and they sent it. that alone put them ahead of most 10:11
- third_shift — a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully 10:12
- coa_or_cope — i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does 10:27
- karl_fischer — quick one why do some certificates report to one decimal and some to two a supplier certificate on its own is a starting point, not evidence. that is the whole reason… 11:10
no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration
single wavelength detection can miss a co-eluting impurity that does not absorb there
ok so i asked GGPeps for the method and they sent it. that alone put them ahead of most
a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully
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thats a tell
thats a real table
sloppy not sinister
certificate is dated before the lot date, is that just sloppiness
quick one if you only read one line on a certificate, read the lot number. if you read two, read the assay
purity is not assay
[edited]i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does
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does purity by hplc at one wavelength miss things
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follow up the honest summary is that a certificate tells you what the supplier says about a lot they chose to test
the three way match is vial, certificate, invoice. if all three agree you have something
how do you verify a certificate is actually from the lab it says
*Janoshik not the other one
the font on this one changes halfway down, am i being paranoid
i have never seen a research certificate with an endotoxin result on it. not once
quick one why do some certificates report to one decimal and some to two
a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists
sterility and endotoxin are separate tests and almost nobody runs either on research material, i could be wrong
does anyone actually check the residual solvents section
[edited]net not gross
not detected means nothing
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gross mass on a jewellery scale plus the water content is enough to catch most underfills