how do you verify a certificate is actually from the lab it says
no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration
#coa-reading 2025-10-09
Thursday34 messages6 participantstimes are UTC
Highlights from this day
- hair_month_four — the certificate from QST is the one i use to teach this because it actually has a populated impurity table 22:16
- deamidation — i asked ERP for the method and they sent it. that alone put them ahead of most 22:20
- hair_month_four — sorry to jump in the three way match is vial, certificate, invoice. if all three agree you have something 22:47
- VialBot — Recon calculator: 20mg in 3ml = 4mg/ml. 23:27
a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully
thats a real table
🙏9✅9💀1
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
retention time shifts between runs are normal. relative retention time is the number to compare
does anyone keep a folder of certificates to compare over time
ask for water content
gross mass on a jewellery scale plus the water content is enough to catch most underfills
sloppy not sinister
whats the related substances table actually telling me
an identical chromatogram on two different lots is the single biggest tell there is
the certificate from QST is the one i use to teach this because it actually has a populated impurity table
i asked ERP for the method and they sent it. that alone put them ahead of most
weigh the vial
🔥1👀1🎉7
follow up water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it, we shall see
is water content normally on a certificate or do you have to ask
the honest summary is that a certificate tells you what the supplier says about a lot they chose to test
looks re-dated
🤝2👀5
why do some certificates report to one decimal and some to two
test it yourself
the font on this one changes halfway down, am i being paranoid
unrelated but i keep every certificate in a dated folder and compare them. two suppliers had not changed their template since 2019
is sterility tested as part of a normal purity certificate
sorry to jump in the three way match is vial, certificate, invoice. if all three agree you have something
the paperwork can be perfect and the vial can still be light. weigh it
purity is not assay
🧊6
is endotoxin ever tested on research material
should a certificate say which instrument and method they used
i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does
certificate is dated before the lot date, is that just sloppiness
tfa or acetate, how do i tell from the paperwork
what does net peptide content mean next to gross mass
Recon calculator: 20mg in 3ml = 4mg/ml.