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.
Analytics in 2024
Page 6 of 10 of this archive, newest first.
What Medutest charges to answer the pyrogen question
The masking phenomenon known as low endotoxin recovery means a formulation can return a clean result while containing endotoxin the assay cannot see.
Independent analysis puts a CPC orforglipron lot at 96.1%, against 94.6% on the certificate
The supplier has not disputed the finding. It has not explained the gap either.
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…
Independent analysis puts a CPC orforglipron lot at 95.2%, against 92.3% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
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.
Independent analysis puts a SGN liraglutide lot at 95.7%, against 93.4% on the certificate
The supplier has not disputed the finding. It has not explained the gap either.
The question no chromatogram has ever answered
Every certificate circulating in this market answers a question about molecules. Almost none answers a question about organisms, pyrogens, or the integrity of the seal.
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.
PeptideMeter result on a Tianjin mazdutide lot lands 4.3 points below the supplier’s figure
The supplier has not disputed the finding. It has not explained the gap either.
Three services, one lot, and a spread of two and a half points
Duplicate submissions under different names test within-laboratory repeatability, which is a different quantity from between-laboratory reproducibility.
Four ways a peptide comes apart
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.
Independent analysis puts a WWB survodutide lot at 99.2%, against 95.5% on the certificate
The supplier has not disputed the finding. It has not explained the gap either.
Endotoxin is not a microorganism, and killing the bacteria does not remove it
Three compendial method families are in routine use and a fourth, based on a recombinant enzyme rather than crab lysate, is now compendial in its own right.
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.
VendorInvestigate result on a Zhuhai dulaglutide lot lands 2.6 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 QST cagrilintide lot at 98.4%, against 96.0% on the certificate
The supplier has not disputed the finding. It has not explained the gap either.
Quadrupole, time-of-flight, orbital trap: what each class can and cannot see
Every instrument specification quoted in an advertisement is a best case obtained on a calibration mixture, not on a submitted vial.
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.