mixed fonts and inconsistent kerning in one document is worth a second look
#coa-reading 2025-02-02
Sunday29 messages7 participantstimes are UTC
Highlights from this day
- area_percent — a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully, ymmv 10:01
- week_zero — i asked ERP for the method and they sent it. that alone put them ahead of most 10:04
- week_zero — what does net peptide content mean next to gross mass 10:55
- electrolyte_eli — retention time shifts between runs are normal. relative retention time is the number to compare 14:55
- reta_resting_hr — the paperwork can be perfect and the vial can still be light. weigh it the related substances table is the interesting part. a row of "not detected" means they did… 17:32
my 5mg vial weighed more than 15mg of powder, is the certificate lying
[edited]i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does
thats the counterion
🙏7
ask for water content
whats the related substances table actually telling me
sterility and endotoxin are separate tests and almost nobody runs either on research material
a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully, ymmv
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i asked ERP for the method and they sent it. that alone put them ahead of most
is there a standard layout or does every lab do their own
no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration
what does net peptide content mean next to gross mass
😂14
thats a real table
not evidence on its own
a certificate should name the method, the instrument, the column and the operator. most name none of those
is water content normally on a certificate or do you have to ask
not detected means nothing
check the lot
single wavelength detection can miss a co-eluting impurity that does not absorb there
if you only read one line on a certificate, read the lot number. if you read two, read the assay
purity is what fraction of the contents is the target. assay is how many mg are actually there. different questions
residual solvents matter more than people think for anything that went through a lot of purification steps
if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not
retention time shifts between runs are normal. relative retention time is the number to compare
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does anyone keep a folder of certificates to compare over time
nobody can authenticate a certificate from a scan. you authenticate the material by testing it yourself
no lot number on this certificate, does that make it worthless
two certificates from the same supplier have an identical chromatogram, is that normal
the paperwork can be perfect and the vial can still be light. weigh it
the related substances table is the interesting part. a row of "not detected" means they did not look hard