is a supplier certificate worth anything on its own
#coa-reading 2025-10-19
Sunday25 messages7 participantstimes are UTC
Highlights from this day
- power_cut_pia — why would a vial be 98.1 pure and still assay under label 13:51
- endotoxin_ed — slightly off topic but one decimal versus two is usually just house style, not precision 15:10
- travel_cooler — the related substances table is the interesting part. a row of "not detected" means they did not look hard 18:18
the font on this one changes halfway down, am i being paranoid
a certificate should name the method, the instrument, the column and the operator. most name none of those, for what its worth
the three way match is vial, certificate, invoice. if all three agree you have something
single wavelength detection can miss a co-eluting impurity that does not absorb there
is area percent the same thing as how many mg are in the vial
if you only read one line on a certificate, read the lot number. if you read two, read the assay
why would a vial be 98.1 pure and still assay under label
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a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully
water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it
ok so the paperwork can be perfect and the vial can still be light. weigh it
residual solvents matter more than people think for anything that went through a lot of purification steps, anyway
not evidence on its own
retention time shifts between runs are normal. relative retention time is the number to compare
tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance
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the honest summary is that a certificate tells you what the supplier says about a lot they chose to test, i think
the three way match is vial, certificate, invoice. if all three agree you have something
is there a standard layout or does every lab do their own
slightly off topic but one decimal versus two is usually just house style, not precision
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does anyone actually check the residual solvents section
a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists
is endotoxin ever tested on research material
does anyone keep a folder of certificates to compare over time
two certificates from the same supplier have an identical chromatogram, is that normal
a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully
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quick one tfa or acetate, how do i tell from the paperwork
the related substances table is the interesting part. a row of "not detected" means they did not look hard
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certificate is dated before the lot date, is that just sloppiness