The question no chromatogram has ever answered
The Journal has read several hundred certificates from twenty companies. We set out what the documents actually cover, and what a reader is filling in from imagination.
Félix Oyarzún
Page 6 of 7 of this archive, newest first.
Archive — page 6
134 piecesWhat 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.
Electrospray, MALDI, and the choice that shapes every spectrum after it
A brief and unromantic tour of the interface between a liquid sample and a vacuum.
The four testing services and the study none of them can run
Storage instructions in this market are close to uniform and almost never accompanied by the study that would justify them. Uniformity is a sign of convention, not of…
The reference change value: the number that tells you whether a delta is real
The arithmetic of the reference change value, worked for the analytes that matter here.
Independent analysis puts a TFC mazdutide lot at 98.1%, against 94.2% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
Collapse temperature, and the hour of the cycle where shelf life is lost
Lyophilisation does not stop degradation. It slows every pathway by removing the solvent that most of them require, and the residue of solvent that remains sets the rate.
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.
Eating enough protein on a suppressed appetite is an arithmetic problem before it is a nutritional one
The practical difficulty is not knowing the target. It is meeting it on an appetite that has been pharmacologically reduced by half.
Independent analysis puts a ERP cagrilintide lot at 95.3%, against 91.4% on the certificate
The result is unremarkable. What the report omits is not.
Benzyl alcohol is a preservative, not a sterilising agent
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 four testing services and the study none of them can run
What would make a difference is not a regulator. It is three lines on a certificate, all of which are already known to whoever wrote it.
The four testing services and the study none of them can run
Storage instructions in this market are close to uniform and almost never accompanied by the study that would justify them. Uniformity is a sign of convention, not of…
Janoshik result on a Nantong exenatide lot lands 3.1 points below the supplier’s figure
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
How a release document is put together in a regulated plant
The purity figure is the least informative line on a well-constructed certificate and the only line most buyers read.
Independent analysis puts a WXT semaglutide lot at 98.8%, against 95.3% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
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.
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.
How to audit an identity claim in five minutes
The regulated world states the method, the instrument, the convention and the tolerance. This market states a verdict.
Reading HbA1c in the presence of anaemia
A robust, cheap, standardised assay with a specific and well-catalogued set of failure modes, several of which are common in this population.