#coa-reading 2026-03-20

Friday13 messages3 participantstimes are UTC

Highlights from this day

nordic_price_nils — update on the earlier thing residual solvents matter more than people think for anything that went through a lot of purification steps 11:50
nordic_price_nils — water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it 13:07
nordic_price_nils — unrelated but my 30mg vial weighed more than 30mg of powder, is the certificate lying 13:20
two_ml_two — gross mass on a jewellery scale plus the water content is enough to catch most underfills 13:23
nordic_price_nils — tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance if the certificate date precedes the lot date, ask.… 13:35

update on the earlier thing residual solvents matter more than people think for anything that went through a lot of purification steps

nordic_price_nils 12:50

what does net peptide content mean next to gross mass

warsaw_vial 12:52

check the lot

net not gross

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 substance

while im here no lot number on this certificate, does that make it worthless

nordic_price_nils 13:07

water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it

🎉11

nordic_price_nils 13:19

thats the counterion

unrelated but my 30mg vial weighed more than 30mg of powder, is the certificate lying

✅2📈12🎉11

two_ml_two 13:23

gross mass on a jewellery scale plus the water content is enough to catch most underfills

❤️1

nordic_price_nils 13:35

tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance
if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not

nordic_price_nils 13:44

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

two_ml_two 13:46

coming back after 22 months, has the pinned reading guide changed

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