Independent analysis puts a BCH mazdutide lot at 96.0%, against 93.7% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
Independent testing
Page 4 of 27 of this archive, newest first.
An interlaboratory comparison nobody had run
Duplicate submissions under different names test within-laboratory repeatability, which is a different quantity from between-laboratory reproducibility.
PeptideMeter result on a Guangzhou exenatide lot lands 4.3 points below the supplier’s figure
The result is unremarkable. What the report omits is not.
Independent analysis puts a GGPeps cagrilintide lot at 99.2%, against 95.1% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
The header, the table and the signature block
The header identifies the batch, the table records the tests, and the footer says who is answerable. Two of the three are usually incomplete.
Accreditation, scope, and the question nobody asks Medutest
What the Journal asks when a document arrives unsigned, and what the answers have been.
A named analyst is the cheapest quality signal in this trade
Somebody has to be answerable for a release document. On most certificates in this market, nobody is named at all.
Endotoxin is not a microorganism, and killing the bacteria does not remove it
Three compendial method families are in routine use and a fourth, based on a recombinant enzyme rather than crab lysate, is now compendial in its own right.
VendorInvestigate result on a Chengdu tirzepatide lot lands 3.4 points below the supplier’s figure
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
PeptideMeter result on a Wuhan mazdutide lot lands 2.3 points below the supplier’s figure
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
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 SGN survodutide lot at 95.6%, against 93.1% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
What orthogonal actually means, and what it does not
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 Shanghai tirzepatide lot lands 1.3 points below the supplier’s figure
The result is unremarkable. What the report omits is not.
Independent analysis puts a QSC survodutide lot at 99.4%, against 95.9% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
How a claim degrades between the bench and the listing
A badge asserts that something was tested. It does not assert what, when, on whose sample, by what method, or whether the lot on sale is the lot that was tested.
An interlaboratory comparison nobody had run
The Journal submitted split samples from single lots to three assay services, under names unconnected to this publication, and published each method alongside each result.
Janoshik, Medutest, PeptideMeter, VendorInvestigate: a capability audit
The absence of microbiological capability in this market is a commercial fact with a straightforward explanation, and it is worth understanding before blaming anybody for it.
Quadrupole, time-of-flight, orbital trap: what each class can and cannot see
Calibration drift is real, unremarkable, and the reason serious laboratories run internal standards.
Independent analysis puts a SWB tirzepatide lot at 98.3%, against 95.6% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.