is endotoxin ever tested on research material
#coa-reading 2026-02-26
Thursday22 messages5 participantstimes are UTC
Highlights from this day
- travel_cooler — the certificate from GL Biochem is the one i use to teach this because it actually has a populated impurity table 00:12
- travel_cooler — sorry to jump in tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance 00:31
- dana_titrates — quick one i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does 02:28
if you only read one line on a certificate, read the lot number. if you read two, read the assay
the certificate from GL Biochem is the one i use to teach this because it actually has a populated impurity table
coming back after 26 months, has the pinned reading guide changed
tfa or acetate, how do i tell from the paperwork
sorry to jump in tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance
the related substances table is the interesting part. a row of "not detected" means they did not look hard
one decimal versus two is usually just house style, not precision
check the lot
same chromatogram
the paperwork can be perfect and the vial can still be light. weigh it
certificate is dated before the lot date, is that just sloppiness
not detected means nothing
sloppy not sinister
if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not
whats the minimum a certificate has to have before you take it seriously
net peptide is gross mass minus water minus counterion. that is why 11.4mg of powder can be a correct 10mg vial, anyway
residual solvents matter more than people think for anything that went through a lot of purification steps
thats a real table
quick one i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does
is water content normally on a certificate or do you have to ask
does purity by hplc at one wavelength miss things