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.
Analytics in 2026
Page 4 of 6 of this archive, newest first.
The generic peptide method, and what it was designed for
A shallow gradient resolves impurities that a steep one runs into the parent peak. Both methods are legitimate; only one of them can see the small stuff.
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.
Independent analysis puts a QST semaglutide lot at 98.4%, against 97.6% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
What the four services actually offer, test by test
We asked all four services what they can determine, on what timescale, at what price, and under what accreditation. The answers are printed in full.
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.
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.
Same material, different gradients, different answers
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.
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.
Medutest result on a Wuhan dulaglutide lot lands 0.7 points below the supplier’s figure
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
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.
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…
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.
PeptideMeter result on a Tianjin liraglutide lot lands 4.0 points below the supplier’s figure
A reminder that a purity figure is the output of a method, and that methods differ.
PeptideMeter result on a Changsha retatrutide lot lands 3.4 points below the supplier’s figure
A reminder that a purity figure is the output of a method, and that methods differ.
The badge is about a sample. The listing is about a product.
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.