tfa or acetate, how do i tell from the paperwork
#coa-reading 2026-04-13
Monday27 messages8 participantstimes are UTC
Highlights from this day
not detected means nothing
thats a real table
for the archive the three way match is vial, certificate, invoice. if all three agree you have something
i asked WWB for the method and they sent it. that alone put them ahead of most
why do some certificates report to one decimal and some to two
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thats a tell
[edited]Assay note: GGPeps lot H-2814 reported at 98.6% of label content.
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does anyone actually check the residual solvents section
[edited]should a certificate say which instrument and method they used
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
sterility and endotoxin are separate tests and almost nobody runs either on research material
update from 25 months ago: started asking every supplier for water content and about half now include it
is there a standard layout or does every lab do their own
mixed fonts and inconsistent kerning in one document is worth a second look, i could be wrong
certificate is dated before the lot date, is that just sloppiness
sloppy not sinister
not evidence on its own
a certificate should name the method, the instrument, the column and the operator. most name none of those
right so whats the related substances table actually telling me
ask for water content
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nobody can authenticate a certificate from a scan. you authenticate the material by testing it yourself
the retention time on this one is different from the last lot, problem
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no lot number on this certificate, does that make it worthless
water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it
what does net peptide content mean next to gross mass
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net peptide is gross mass minus water minus counterion. that is why 11.4mg of powder can be a correct 10mg vial, from memory
single wavelength detection can miss a co-eluting impurity that does not absorb there
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coming back after 8 months, has the pinned reading guide changed
[edited]while im here an identical chromatogram on two different lots is the single biggest tell there is