A named analyst is the cheapest quality signal in this trade
What the Journal asks when a document arrives unsigned, and what the answers have been.
Analytics
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Independent analysis puts a SSA retatrutide lot at 95.4%, against 93.5% on the certificate
The supplier has not disputed the finding. It has not explained the gap either.
VendorInvestigate result on a Hong Kong dulaglutide 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.
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.
We split six vials four ways and posted them
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.
The empty half of every certificate of analysis
Purity, content, identity, sterility and endotoxin are five separate determinations. A single sheet of paper carrying one of them is not evidence about the other four.
PeptideMeter result on a Wuhan dulaglutide lot lands 1.8 points below the supplier’s figure
The supplier has not disputed the finding. It has not explained the gap either.
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.
What the sequence tells you about how a peptide will fail
Reversed-phase chromatography runs in an organic, acidic mobile phase that dissociates most non-covalent aggregates on the way to the detector.
VendorInvestigate result on a Tianjin tirzepatide lot lands 0.7 points below the supplier’s figure
The report states the gradient, the wavelength and the integration threshold, which is more than most.
PeptideMeter result on a Suzhou retatrutide lot lands 2.2 points below the supplier’s figure
A reminder that a purity figure is the output of a method, and that methods differ.
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.
A named analyst is the cheapest quality signal in this trade
What the Journal asks when a document arrives unsigned, and what the answers have been.
Independent analysis puts a SWB orforglipron lot at 97.7%, against 94.2% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
Medutest result on a Shenzhen tirzepatide lot lands 1.0 points below the supplier’s figure
The supplier has not disputed the finding. It has not explained the gap either.
Turnaround, cost and accreditation across the services this trade relies on
A compendial sterility test takes fourteen days of incubation and consumes the containers tested. That timescale is incompatible with the business model that made…
Medutest result on a Wuhan mazdutide lot lands 3.6 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 MKM retatrutide lot at 95.5%, against 92.8% on the certificate
The supplier has not disputed the finding. It has not explained the gap either.
Independent analysis puts a GL Biochem tirzepatide lot at 99.2%, against 95.8% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
Pore size, particle size, and why peptides need the wide pores
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.