is area percent the same thing as how many mg are in the vial
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#coa-reading 2026-04-11
Saturday23 messages8 participantstimes are UTC
Highlights from this day
- VialBot — New independent result logged — FGP, lot KP-0925, purity 97.4% (PeptideMeter). 22:44
- the_bet_2026 — purity is what fraction of the contents is the target. assay is how many mg are actually there. different questions 23:19
- same_chromato — the certificate from WWB is the one i use to teach this because it actually has a populated impurity table 23:40
i asked JEEP for the method and they sent it. that alone put them ahead of most
New independent result logged — FGP, lot KP-0925, purity 97.4% (PeptideMeter).
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the retention time on this one is different from the last lot, problem
thats the counterion
coming back to this is water content normally on a certificate or do you have to ask
purity is not assay
thats a real table
not evidence on its own
a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully
sorry to jump in an identical chromatogram on two different lots is the single biggest tell there is
residual solvents matter more than people think for anything that went through a lot of purification steps
not detected means nothing
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
[edited]purity is what fraction of the contents is the target. assay is how many mg are actually there. different questions
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quick one tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance
weigh the vial
sterility and endotoxin are separate tests and almost nobody runs either on research material
the certificate from WWB is the one i use to teach this because it actually has a populated impurity table
why would a vial be 99 pure and still assay under label
gross mass on a jewellery scale plus the water content is enough to catch most underfills, still working it out
the honest summary is that a certificate tells you what the supplier says about a lot they chose to test