same chromatogram
#coa-reading 2025-08-05
Tuesday11 messages4 participantstimes are UTC
Highlights from this day
- HPLC_Hank — i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does 18:59
- HPLC_Hank — mixed fonts and inconsistent kerning in one document is worth a second look 19:04
- nausea_window — the retention time on this one is different from the last lot, problem 19:06
a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully
Reminder for salt_bridge: dose day is today. Set 9 days ago.
i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does
[edited]| Line | Claims | Does not claim |
|---|---|---|
| Purity (area %) | fraction of detected material that is the target | how many mg are in the vial |
| Assay / content | mg of target per vial | that it is sterile |
| Water content | mass fraction that is water | anything about purity |
| Counterion | salt form and its mass share | net peptide unless stated |
| Related substances | what else was seen | what was not looked for |
🙏7💀10
mixed fonts and inconsistent kerning in one document is worth a second look
🧊12📈13
the retention time on this one is different from the last lot, problem
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 substancetfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance
sloppy not sinister
Reminder set. I will post here in 3 days.
why do some certificates report to one decimal and some to two
update on the earlier thing if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not