PeptideMeter result on a Guangzhou orforglipron lot lands 3.3 points below the supplier’s figure
A reminder that a purity figure is the output of a method, and that methods differ.
Analytics in 2024
Page 7 of 10 of this archive, newest first.
What a laboratory knows about the material it receives
Chain of custody, in a regulated setting, begins at sampling. Here it begins when the package arrives.
Endotoxin is not a microorganism, and killing the bacteria does not remove it
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.
PeptideMeter result on a Changsha liraglutide 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.
Independent analysis puts a Homopeptide cagrilintide lot at 98.1%, against 94.7% on the certificate
The supplier has not disputed the finding. It has not explained the gap either.
Where the solvent front ends is a decision, not a fact
We work through a single chromatogram twice, under two integration conventions, and show where the difference comes from.
Janoshik result on a Suzhou tirzepatide lot lands 4.1 points below the supplier’s figure
The result is unremarkable. What the report omits is not.
Independent analysis puts a HJ orforglipron lot at 95.8%, against 93.6% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
VendorInvestigate result on a Zhuhai survodutide lot lands 0.9 points below the supplier’s figure
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
Independent analysis puts a QST survodutide lot at 96.3%, against 95.4% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
Manual reintegration is legitimate, and it should be declared
We work through a single chromatogram twice, under two integration conventions, and show where the difference comes from.
PeptideMeter result on a Chengdu exenatide lot lands 3.6 points below the supplier’s figure
The supplier has not disputed the finding. It has not explained the gap either.
Six words a verification badge would need to mean anything
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.
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.
VendorInvestigate result on a Qingdao retatrutide lot lands 3.6 points below the supplier’s figure
A reminder that a purity figure is the output of a method, and that methods differ.
Independent analysis puts a GL Biochem exenatide lot at 98.1%, against 96.5% 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
At low concentrations a measurable fraction of peptide can adsorb to glass and plastic surfaces, and the loss is largest exactly where it is least expected.
The number at the bottom of the certificate
A purity percentage is the most quoted figure in the research-peptide trade and one of the least examined. We asked four laboratories to analyse the same vial and got four…
Independent analysis puts a WXT semaglutide lot at 98.0%, against 95.7% on the certificate
The result is unremarkable. What the report omits is not.
VendorInvestigate result on a Wuhan orforglipron lot lands 3.8 points below the supplier’s figure
The supplier has not disputed the finding. It has not explained the gap either.