check the lot
#coa-reading 2026-05-18
Monday16 messages3 participantstimes are UTC
Highlights from this day
- brisbane_bac — while im here a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists 07:57
- brisbane_bac — 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, we shall see 07:59
- comment_fatigue — ok so net peptide is gross mass minus water minus counterion. that is why 11.4mg of powder can be a correct 10mg vial water content is why an honest 10mg vial assays… 08:01
- a1c_lag — slightly off topic but a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully 09:10
- a1c_lag — i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does 09:11
nobody can authenticate a certificate from a scan. you authenticate the material by testing it yourself
no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration
one decimal versus two is usually just house style, not precision
if you only read one line on a certificate, read the lot number. if you read two, read the assay
while im here a supplier certificate on its own is a starting point, not evidence. that is the whole reason the verification channel exists
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, we shall see
the retention time on this one is different from the last lot, problem
ok so net peptide is gross mass minus water minus counterion. that is why 11.4mg of powder can be a correct 10mg vial
water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it
does purity by hplc at one wavelength miss things
thats a real table
is area percent the same thing as how many mg are in the vial
slightly off topic but a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully
i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does
whats the minimum a certificate has to have before you take it seriously
is endotoxin ever tested on research material