A percentage is not a specification
Chromatographic purity is cheap, fast and comparable-looking. Those three properties, and not its usefulness, explain why it became the industry’s single figure of merit.
Purity
Page 51 of 51 of this archive, newest first.
What “LC-MS: conforms” tells a reader, which is almost nothing
A short audit procedure, usable by anyone holding a certificate and a calculator.
PeptideMeter result on a Guangzhou semaglutide lot lands 1.0 points below the supplier’s figure
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
Sending the same vial twice, under two names
Two years ago we ran an anonymised version of this comparison and promised a named one. This is it, with every method printed in full.
New Zealand health authority warns on falsified tirzepatide pens
Reported from the analysis, not from a warning notice.
VendorInvestigate result on a Xi'an retatrutide lot lands 1.1 points below the supplier’s figure
The supplier has not disputed the finding. It has not explained the gap either.
What changed at WXT in January, and what the company will not say about it
Documentation practice is the only part of vendor quality a buyer can assess before purchase.
Low endotoxin recovery: the interference nobody looks for
We submitted vials for endotoxin determination and report the results, the method and the laboratory, because a pyrogen figure without a method is as empty as a purity…
What the paperwork is for, and who it was designed to protect
The header identifies the batch, the table records the tests, and the footer says who is answerable. Two of the three are usually incomplete.
Independent analysis puts a MKM cagrilintide lot at 98.9%, against 94.9% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
From vial to bench: what is recorded and what is assumed
Chain of custody, in a regulated setting, begins at sampling. Here it begins when the package arrives.
Holograms, QR codes and other things that are not verification
Reported from the analysis, not from a warning notice.
What changed at CPC in January, and what the company will not say about it
Documentation practice is the only part of vendor quality a buyer can assess before purchase.
Spain health authority warns on falsified liraglutide pens
Reported from the analysis, not from a warning notice.
Medutest result on a Xianning orforglipron lot lands 2.7 points below the supplier’s figure
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
What changed at Homopeptide in January, and what the company will not say about it
Documentation practice is the only part of vendor quality a buyer can assess before purchase.
What changed at GL Biochem in January, and what the company will not say about it
Documentation practice is the only part of vendor quality a buyer can assess before purchase.
Independent analysis puts a BCH semaglutide lot at 95.2%, against 91.2% on the certificate
The supplier has not disputed the finding. It has not explained the gap either.
A tested vial is evidence about a vial
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.
What changed at WXT in January, and what the company will not say about it
Documentation practice is the only part of vendor quality a buyer can assess before purchase.