why do some certificates report to one decimal and some to two
#coa-reading 2026-05-08
Friday18 messages5 participantstimes are UTC
Highlights from this day
- karl_fischer — sterility and endotoxin are separate tests and almost nobody runs either on research material 19:37
- dark_for_ten_days — i asked GGPeps for the method and they sent it. that alone put them ahead of most 19:43
- loam_logs — a vial can be 99.4% pure and hold 8.1mg of a 10mg label. both numbers are true and only one of them is the one you care about 19:59
net not gross
is sterility tested as part of a normal purity certificate
the related substances table is the interesting part. a row of "not detected" means they did not look hard
is there a standard layout or does every lab do their own
sterility and endotoxin are separate tests and almost nobody runs either on research material
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single wavelength detection can miss a co-eluting impurity that does not absorb there
tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance
i asked GGPeps for the method and they sent it. that alone put them ahead of most
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no lot no certificate
coming back after 19 months, has the pinned reading guide changed
genuine question an identical chromatogram on two different lots is the single biggest tell there is
one decimal versus two is usually just house style, not precision, for what its worth
i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does
check the lot
[edited]a vial can be 99.4% pure and hold 8.1mg of a 10mg label. both numbers are true and only one of them is the one you care about
ask for water content
if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not