The instrument was calibrated on Tuesday. Your sample ran on Friday.
Parts per million sound impressive until they are converted into daltons at the molecular weight of the thing being measured.
Purity
Page 24 of 51 of this archive, newest first.
VendorInvestigate result on a Xianning cagrilintide lot lands 2.6 points below the supplier’s figure
The result is unremarkable. What the report omits is not.
The impurity hiding underneath the parent peak
Where two methods disagree, the conservative convention is to report the lower figure. It is not universal, and whether a laboratory follows it belongs on the report.
Independent analysis puts a Homopeptide retatrutide lot at 98.9%, against 98.1% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
Nought point nine eight of a dalton: the modification that hides in plain sight
Stereochemical inversion changes the molecule, changes its biology, and changes its mass by exactly nothing.
Change the pH and the co-elution moves
An orthogonal method separates on a different physical principle, so that species co-eluting in the first are likely to resolve in the second. Two runs of the same method at…
Holograms, QR codes and other things that are not verification
Reported from the analysis, not from a warning notice.
How a claim degrades between the bench and the listing
Lot-level verification with a public report is a real and achievable thing. It exists in this market, on a minority of listings.
Holograms, QR codes and other things that are not verification
Reported from the analysis, not from a warning notice.
Oxidation, and the peroxide that came in with the surfactant
An isoaspartate rearrangement changes the molecule and not the mass. A method that confirms identity by molecular weight alone will report it as the parent compound.
Turkey health authority warns on falsified semaglutide pens
Reported from the analysis, not from a warning notice.
Holograms, QR codes and other things that are not verification
Reported from the analysis, not from a warning notice.
What a laboratory knows about the material it receives
A result on one vial generalises to a batch only if the vial was drawn in a way that makes it representative — and nobody records how it was drawn.
Denmark health authority warns on falsified semaglutide pens
Reported from the analysis, not from a warning notice.
What counts as total, and who decided
We work through a single chromatogram twice, under two integration conventions, and show where the difference comes from.
Independent analysis puts a QYB dulaglutide lot at 99.3%, against 98.0% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
Freezing a reconstituted vial: the ice-water interface problem
Every degradation pathway accelerates by orders of magnitude on reconstitution, because the solvent that lyophilisation removed is the reagent most of them need.
Holograms, QR codes and other things that are not verification
Reported from the analysis, not from a warning notice.
Sterility is not a percentage, which is the whole difficulty
Purity, content, identity, sterility and endotoxin are five separate determinations. A single sheet of paper carrying one of them is not evidence about the other four.
Holograms, QR codes and other things that are not verification
Reported from the analysis, not from a warning notice.