#coa-reading 2025-07-24

residual solvents matter more than people think for anything that went through a lot of purification steps
the honest summary is that a certificate tells you what the supplier says about a lot they chose to test

net not gross

is endotoxin ever tested on research material

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

mixed fonts and inconsistent kerning in one document is worth a second look, n of 1 obviously

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

how do you verify a certificate is actually from the lab it says

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

tfa or acetate, how do i tell from the paperwork

the paperwork can be perfect and the vial can still be light. weigh it

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

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

test it yourself

one decimal versus two is usually just house style, not precision

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

if you only read one line on a certificate, read the lot number. if you read two, read the assay

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

is there a standard layout or does every lab do their own

gross mass on a jewellery scale plus the water content is enough to catch most underfills, i could be wrong

weigh the vial

thats a real table