A document, not a test: what a certificate actually is
The purity figure is the least informative line on a well-constructed certificate and the only line most buyers read.
Analytics in 2024
Page 8 of 10 of this archive, newest first.
Independent analysis puts a GL Biochem tirzepatide lot at 96.7%, against 95.9% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
PeptideMeter result on a Zhuhai cagrilintide lot lands 1.5 points below the supplier’s figure
The report states the gradient, the wavelength and the integration threshold, which is more than most.
How a release document is put together in a regulated plant
Nothing on this page is difficult. It is simply unfamiliar, and unfamiliarity is what makes a weak certificate look like a strong one.
Matrix, laser, needle: the plumbing that determines what you see
A brief and unromantic tour of the interface between a liquid sample and a vacuum.
VendorInvestigate result on a Changsha dulaglutide lot lands 3.5 points below the supplier’s figure
A reminder that a purity figure is the output of a method, and that methods differ.
Same material, different gradients, different answers
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.
Independent analysis puts a SWB dulaglutide lot at 96.2%, against 95.6% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
Twenty-eight days is a number from somebody else’s product
We set out what is known, what is inferred and what is simply assumed about the fortnight after a vial is opened.
Soft ionisation: the twenty-year-old trick that made peptide identity routine
A brief and unromantic tour of the interface between a liquid sample and a vacuum.
Four ways a peptide comes apart
Deamidation, oxidation, aggregation and hydrolysis account for nearly all of what happens to a peptide over time. Each has a characteristic residue, a characteristic…
VendorInvestigate result on a Hong Kong mazdutide lot lands 2.6 points below the supplier’s figure
The result is unremarkable. What the report omits is not.
Independent analysis puts a BCH cagrilintide lot at 96.1%, against 95.2% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
Aggregation: the impurity your chromatogram dissolved before it looked
We describe each pathway in enough chemical detail to explain why it is invisible to the method the trade uses, because that is the part which has practical consequences.
VendorInvestigate result on a Zhuhai semaglutide lot lands 1.1 points below the supplier’s figure
The result is unremarkable. What the report omits is not.
Why a dead-clean sterile filter can pass pyrogen straight through
Bacterial endotoxin is a heat-stable lipopolysaccharide from the outer membrane of Gram-negative organisms. It survives sterilisation, passes a sterilising filter, and is…
Low endotoxin recovery: the interference nobody looks for
The masking phenomenon known as low endotoxin recovery means a formulation can return a clean result while containing endotoxin the assay cannot see.
A tested vial is evidence about a vial
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 named comparison we promised two years ago
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.
Independent analysis puts a WWB liraglutide lot at 98.2%, against 96.5% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.