coming back after 4 months, has the pinned reading guide changed
#coa-reading 2026-05-29
Friday33 messages6 participantstimes are UTC
Highlights from this day
- blank_run — i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does 13:36
- sasha_stacks — a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully, i think 14:42
- split_dose_sam — mixed fonts and inconsistent kerning in one document is worth a second look 15:18
- split_dose_sam — no lot number on this certificate, does that make it worthless 16:05
- shame_and_meds — update on the earlier thing my 5mg vial weighed more than 10mg of powder, is the certificate lying 17:32
the font on this one changes halfway down, am i being paranoid
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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test it yourself
is area percent the same thing as how many mg are in the vial
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
should a certificate say which instrument and method they used
if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not
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the three way match is vial, certificate, invoice. if all three agree you have something
the retention time on this one is different from the last lot, problem
tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance
coa-a-2418.pdf
1 page · 198 KB · not retained in the public archive
why do some certificates report to one decimal and some to two
water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it
a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully, i think
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ok so one decimal versus two is usually just house style, not precision
update from 5 months ago: started asking every supplier for water content and about half now include it
sloppy not sinister
good certificate actually
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update from 11 months ago: started asking every supplier for water content and about half now include it
purity is not assay
coming back to this the related substances table is the interesting part. a row of "not detected" means they did not look hard
Verification log updated: KP — evidence added, status unchanged.
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not evidence on its own
two certificates from the same supplier have an identical chromatogram, is that normal
slightly off topic but whats the minimum a certificate has to have before you take it seriously
mixed fonts and inconsistent kerning in one document is worth a second look
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same chromatogram
no lot number on this certificate, does that make it worthless
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ask for water content
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why would a vial be 99.2 pure and still assay under label
Channel stats, last 30 days: 54 messages from 55 members.
i asked BCH for the method and they sent it. that alone put them ahead of most, thats one data point
looks re-dated
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update on the earlier thing my 5mg vial weighed more than 10mg of powder, is the certificate lying
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whats the related substances table actually telling me
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