does anyone keep a folder of certificates to compare over time
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Thread · #coa-reading · 2026-02-25
whats the related substances table actually telling me
Spun off from a message in #coa-reading on 2026-02-25. 17 messages, 4 participants.
The message this came from
- peak_split — whats the related substances table actually telling me 15:03
thats a real table
the certificate from MKM is the one i use to teach this because it actually has a populated impurity table
single wavelength detection can miss a co-eluting impurity that does not absorb there
purity is not assay
not evidence on its own
nordic_price_nilssingle wavelength detection can miss a co-eluting impurity that does not absorb there
the related substances table is the interesting part. a row of "not detected" means they did not look hard
gross mass on a jewellery scale plus the water content is enough to catch most underfills
looks re-dated
looks re-dated
the certificate from QST is the one i use to teach this because it actually has a populated impurity table
not evidence on its own
the certificate from WWB is the one i use to teach this because it actually has a populated impurity table
ask for water content
two certificates from the same supplier have an identical chromatogram, is that normal
my 10mg vial weighed more than 2mg of powder, is the certificate lying
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retention time shifts between runs are normal. relative retention time is the number to compare
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