retention time shifts between runs are normal. relative retention time is the number to compare
#coa-reading 2025-08-24
Sunday20 messages5 participantstimes are UTC
Highlights from this day
- turnaround_tam — the three way match is vial, certificate, invoice. if all three agree you have something, we shall see 21:33
- third_shift — is area percent the same thing as how many mg are in the vial 22:06
- assay_not_purity — gross mass on a jewellery scale plus the water content is enough to catch most underfills, not advice obviously 22:21
- VialBot — Testing queue: 5 submissions open, 32 awaiting dispatch. 22:26
is a supplier certificate worth anything on its own
why would a vial be 98.6 pure and still assay under label
mixed fonts and inconsistent kerning in one document is worth a second look
the font on this one changes halfway down, am i being paranoid
is endotoxin ever tested on research material
sterility and endotoxin are separate tests and almost nobody runs either on research material
no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration
the three way match is vial, certificate, invoice. if all three agree you have something, we shall see
🧪12
check the lot
peak RRT area% note
1 0.42 0.31 solvent front
2 0.88 0.44 related substance
3 1.00 98.72 main
4 1.14 0.53 related substancewhats the related substances table actually telling me
if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not
no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration
is area percent the same thing as how many mg are in the vial
😂17
update on the earlier thing i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does
i have never seen a research certificate with an endotoxin result on it. not once, someone check my working
not detected means nothing
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
gross mass on a jewellery scale plus the water content is enough to catch most underfills, not advice obviously
lot bought purity assay/label
A-2418 2025-03 99.1% 9.6 / 10mg
A-2601 2025-08 98.7% 9.8 / 10mg
B-0114 2026-01 99.3% 9.4 / 10mg
B-0329 2026-04 98.9% 9.9 / 10mgpurity is what fraction of the contents is the target. assay is how many mg are actually there. different questions
Testing queue: 5 submissions open, 32 awaiting dispatch.