Set the threshold at a tenth of a per cent and the small impurities vanish
We work through a single chromatogram twice, under two integration conventions, and show where the difference comes from.
Recent work
63 piecesIndependent analysis puts a FGP exenatide lot at 95.7%, against 94.1% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
Independent analysis puts a Homopeptide semaglutide lot at 96.0%, against 92.4% on the certificate
The result is unremarkable. What the report omits is not.
PeptideMeter result on a Wuxi dulaglutide lot lands 2.2 points below the supplier’s figure
The report states the gradient, the wavelength and the integration threshold, which is more than most.
LAL, kinetic chromogenic, recombinant factor C: three ways to the same figure
The limit for a parenteral product is calculable from the dose and the body weight in two lines. Almost nobody in this trade performs the calculation.
Independent analysis puts a Homopeptide retatrutide lot at 98.3%, against 97.3% on the certificate
The result is unremarkable. What the report omits is not.
VendorInvestigate result on a Zhuhai survodutide lot lands 4.2 points below the supplier’s figure
The supplier has not disputed the finding. It has not explained the gap either.
Independent analysis puts a MKM survodutide lot at 96.5%, against 95.5% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
Independent analysis puts a FGP exenatide lot at 95.8%, against 93.2% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
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.
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.
The badge economy, and what it is actually certifying
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.
PeptideMeter result on a Zhuhai tirzepatide lot lands 3.5 points below the supplier’s figure
The result is unremarkable. What the report omits is not.
Independent analysis puts a SGN cagrilintide lot at 98.0%, against 96.6% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
The reviewer, the approver, and why regulated documents carry two names
A manufacturer’s certificate is a self-declaration. An accredited laboratory’s report is a third-party measurement. The trade prints both under one heading.
Independent analysis puts a ERP exenatide lot at 95.8%, against 93.5% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
Independent analysis puts a HJ dulaglutide lot at 95.0%, against 93.3% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
Two analysts, one chromatogram, two answers
Chromatographic software does not integrate every fluctuation in the baseline. It applies a threshold, and the threshold changes the reported purity by amounts that matter…
Reading a certificate as a document rather than as a score
Nothing on this page is difficult. It is simply unfamiliar, and unfamiliarity is what makes a weak certificate look like a strong one.
Retest date, expiry date, and the two conventions being confused
A document is only as good as the chain that connects it to the material, and most chains here are two or three links longer than the paperwork admits.