#coa-reading 2026-04-25

tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance

is endotoxin ever tested on research material

purity is what fraction of the contents is the target. assay is how many mg are actually there. different questions

not evidence on its own

same chromatogram

ask for water content

my 5mg vial weighed more than 20mg of powder, is the certificate lying

i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does

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

update on the earlier thing i asked FGP for the method and they sent it. that alone put them ahead of most

net not gross

ok so the three way match is vial, certificate, invoice. if all three agree you have something

the related substances table is the interesting part. a row of "not detected" means they did not look hard

while im here a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully

does purity by hplc at one wavelength miss things
nobody can authenticate a certificate from a scan. you authenticate the material by testing it yourself

i keep every certificate in a dated folder and compare them. two suppliers had not changed their template since 2019

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

an identical chromatogram on two different lots is the single biggest tell there is

a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists