#coa-reading 2026-01-04

one decimal versus two is usually just house style, not precision, ill dig out the number

Assay note: HJ lot A-2418 reported at 99% of label content.

net peptide is gross mass minus water minus counterion. that is why 11.4mg of powder can be a correct 10mg vial

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

the paperwork can be perfect and the vial can still be light. weigh it, thats just me

if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not

should a certificate say which instrument and method they used

check the lot

the honest summary is that a certificate tells you what the supplier says about a lot they chose to test

the certificate from SSA is the one i use to teach this because it actually has a populated impurity table

Reminder for back_from_away: dose day is today. Set 5 days ago.

two certificates from the same supplier have an identical chromatogram, is that normal

single wavelength detection can miss a co-eluting impurity that does not absorb there