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#coa-reading 2025-09-09

Tuesday12 messages5 participantstimes are UTC
Highlights from this day
  • alcohol_hits — quick one a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully 15:18
  • tail_factor — my 15mg vial weighed more than 10mg of powder, is the certificate lying 18:24
  • tail_factor — tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance 18:28
AH
alcohol_hits15:16

net peptide is gross mass minus water minus counterion. that is why 11.4mg of powder can be a correct 10mg vial

quick one a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully

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

is sterility tested as part of a normal purity certificate

TF
tail_factorlab18:23

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

not detected means nothing

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

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