update from 16 months ago: started asking every supplier

thats the counterion

i asked HJ for the method and they sent it. that alone put them ahead of most

sterility and endotoxin are separate tests and almost nobody runs either on research material

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

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

whats the minimum a certificate has to have before you take it seriously