What changed after we published the first version of this
None of what this piece asks for is commercially sensitive, and all of it is already known to whoever released the batch.
Independent testing
Page 6 of 27 of this archive, newest first.
Independent analysis puts a SSA semaglutide lot at 97.6%, against 94.1% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
Leucine, isoleucine, and a difference no balance can measure
Stereochemical inversion changes the molecule, changes its biology, and changes its mass by exactly nothing.
Sending the same vial twice, under two names
Duplicate submissions under different names test within-laboratory repeatability, which is a different quantity from between-laboratory reproducibility.
What the four services actually offer, test by test
A compendial sterility test takes fourteen days of incubation and consumes the containers tested. That timescale is incompatible with the business model that made…
We split six vials four ways and posted them
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.
Independent analysis puts a GL Biochem liraglutide lot at 97.5%, against 93.6% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
Tandem mass spectrometry, and the difference between weighing and reading
An intact mass measurement establishes elemental composition, at best. The number of distinct sequences consistent with a given composition is astronomically large.
Two decimal places, one injection, no procedure
This piece takes the measurement apart into the decisions it is made of, because each decision moves the answer.
Medutest result on a Tianjin exenatide lot lands 2.1 points below the supplier’s figure
A reminder that a purity figure is the output of a method, and that methods differ.
What the four services actually offer, test by test
Four independent services underpin confidence in this market. All four are competent at chemistry. Microbiology is a different accreditation, a different facility and a…
Counter-ion, water, salt: three masses with no chromatogram
The most useful single addition to any purity determination is a second separation under a different pH or on a different stationary phase, and the second-most useful is a…
VendorInvestigate result on a Zhuhai survodutide lot lands 3.8 points below the supplier’s figure
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
Who chose the vial that was tested?
The condition on arrival is recorded by some services and not others, and it is one of the more informative lines in a report.
The submitted sample: the weakest link in the whole system
What a laboratory can and cannot know about the provenance, storage history and representativeness of what lands on its bench.
Independent analysis puts a WWB tirzepatide lot at 98.7%, against 94.6% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
LAL, kinetic chromogenic, recombinant factor C: three ways to the same figure
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…
Why the theoretical mass on the certificate might be the wrong theoretical mass
A worked example: one peptide, five charge states, five mass-to-charge ratios, one molecular weight.
PeptideMeter result on a Zhuhai dulaglutide lot lands 3.7 points below the supplier’s figure
The report states the gradient, the wavelength and the integration threshold, which is more than most.
Independent analysis puts a QSC mazdutide lot at 97.1%, against 93.6% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.