a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully
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#coa-reading 2026-02-23
Monday50 messages9 participantstimes are UTC
Highlights from this day
- auckland_aliquot — a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully 16:39
- auckland_aliquot — tfa or acetate, how do i tell from the paperwork 17:26
- chain_of_custody — right so i asked BCH for the method and they sent it. that alone put them ahead of most i keep every certificate in a dated folder and compare them. two suppliers had… 17:44
- auckland_aliquot — update from 19 months ago: started asking every supplier for water content and about half now include it water content is why an honest 10mg vial assays at 9.1. karl… 17:55
- chain_of_custody — water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it i keep every certificate in a dated folder and compare… 20:03
nobody can authenticate a certificate from a scan. you authenticate the material by testing it yourself
two certificates from the same supplier have an identical chromatogram, is that normal
nobody can authenticate a certificate from a scan. you authenticate the material by testing it yourself
gross mass on a jewellery scale plus the water content is enough to catch most underfills, for what its worth
looks re-dated
does anyone actually check the residual solvents section
no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration
tfa or acetate, how do i tell from the paperwork
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thats a tell
thats the counterion
if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not
if you only read one line on a certificate, read the lot number. if you read two, read the assay
right so i asked BCH for the method and they sent it. that alone put them ahead of most
i keep every certificate in a dated folder and compare them. two suppliers had not changed their template since 2019
no lot no certificate
update from 19 months ago: started asking every supplier for water content and about half now include it
water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it
weigh the vial
retention time shifts between runs are normal. relative retention time is the number to compare
auckland_aliquotnobody can authenticate a certificate from a scan. you authenticate the material by…
my 15mg vial weighed more than 30mg of powder, is the certificate lying
*Janoshik not the other one
i have never seen a research certificate with an endotoxin result on it. not once
a certificate should name the method, the instrument, the column and the operator. most name none of those
is sterility tested as part of a normal purity certificate
one decimal versus two is usually just house style, not precision, not advice obviously
test it yourself
the font on this one changes halfway down, am i being paranoid
i keep every certificate in a dated folder and compare them. two suppliers had not changed their template since 2019
does anyone keep a folder of certificates to compare over time
purity is not assay
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net not gross
net peptide is gross mass minus water minus counterion. that is why 11.4mg of powder can be a correct 10mg vial
certificate is dated before the lot date, is that just sloppiness
the paperwork can be perfect and the vial can still be light. weigh it, someone check my working
the three way match is vial, certificate, invoice. if all three agree you have something
whats the minimum a certificate has to have before you take it seriously
coming back after 14 months, has the pinned reading guide changed
ask for water content
water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it
i keep every certificate in a dated folder and compare them. two suppliers had not changed their template since 2019
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why would a vial be 97.4 pure and still assay under label
same chromatogram
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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sterility and endotoxin are separate tests and almost nobody runs either on research material, i have it written down somewhere
the related substances table is the interesting part. a row of "not detected" means they did not look hard
why do some certificates report to one decimal and some to two
sloppy not sinister
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check the lot
not evidence on its own
is area percent the same thing as how many mg are in the vial
residual solvents matter more than people think for anything that went through a lot of purification steps
update on the earlier thing single wavelength detection can miss a co-eluting impurity that does not absorb there
genuine question purity is what fraction of the contents is the target. assay is how many mg are actually there. different questions, your mileage will differ