certificate is dated before the lot date, is that just sloppiness
#coa-reading 2025-04-19
Saturday40 messages8 participantstimes are UTC
Highlights from this day
- shame_and_meds — mixed fonts and inconsistent kerning in one document is worth a second look a certificate should name the method, the instrument, the column and the operator. most… 15:18
- VialBot — Recon calculator: 30mg in 1.5ml = 2.5mg/ml. 15:21
- VialBot — On this day 5 years ago this channel logged 14 messages. 15:34
- declared_value — one decimal versus two is usually just house style, not precision 16:36
- shame_and_meds — the certificate from JEEP is the one i use to teach this because it actually has a populated impurity table 20:40
mixed fonts and inconsistent kerning in one document is worth a second look
a certificate should name the method, the instrument, the column and the operator. most name none of those
*VendorInvestigate not the other one
Recon calculator: 30mg in 1.5ml = 2.5mg/ml.
same chromatogram
a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully
On this day 5 years ago this channel logged 14 messages.
is endotoxin ever tested on research material
no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration
*VendorInvestigate not the other one
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
genuine question a certificate should name the method, the instrument, the column and the operator. most name none of those
does anyone actually check the residual solvents section
is a supplier certificate worth anything on its own
sorry to jump in single wavelength detection can miss a co-eluting impurity that does not absorb there
is area percent the same thing as how many mg are in the vial
i have never seen a research certificate with an endotoxin result on it. not once
unrelated but tfa or acetate, how do i tell from the paperwork
one decimal versus two is usually just house style, not precision
lot bought purity assay/label
A-2418 2025-03 99.1% 9.6 / 10mg
A-2601 2025-08 98.7% 9.8 / 10mg
B-0114 2026-01 99.3% 9.4 / 10mg
B-0329 2026-04 98.9% 9.9 / 10mgi keep every certificate in a dated folder and compare them. two suppliers had not changed their template since 2019
sloppy not sinister
why would a vial be 98.6 pure and still assay under label
my 40mg vial weighed more than 20mg of powder, is the certificate lying
ask for water content
if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not, someone check my working
does purity by hplc at one wavelength miss things
[edited]if you only read one line on a certificate, read the lot number. if you read two, read the assay
not detected means nothing
an identical chromatogram on two different lots is the single biggest tell there is, someone check my working
thats a real table
genuine question residual solvents matter more than people think for anything that went through a lot of purification steps
sterility and endotoxin are separate tests and almost nobody runs either on research material
water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it
two certificates from the same supplier have an identical chromatogram, is that normal
the retention time on this one is different from the last lot, problem
a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists, for what its worth
test it yourself
peak RRT area% note
1 0.42 0.31 solvent front
2 0.88 0.44 related substance
3 1.00 98.72 main
4 1.14 0.53 related substancedoes anyone keep a folder of certificates to compare over time
retention time shifts between runs are normal. relative retention time is the number to compare
the certificate from JEEP is the one i use to teach this because it actually has a populated impurity table
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