Retest date, expiry date, and the two conventions being confused
A document is only as good as the chain that connects it to the material, and most chains here are two or three links longer than the paperwork admits.
Peptide content
Page 3 of 10 of this archive, newest first.
Who signed this, and what did they undertake by signing it
Accreditation is granted for a defined scope of methods. A laboratory can be properly accredited and the test on your certificate can sit outside it.
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.
What column temperature does to selectivity
We set out the parameters a method disclosure would contain, all of which are known to whoever ran the sample and none of which is commercially sensitive.
Same material, different gradients, different answers
Duplicate submissions under different names test within-laboratory repeatability, which is a different quantity from between-laboratory reproducibility.
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.
Retention time is not identity
Matching a retention time against a standard is evidence of consistency, not proof of identity. Two different species can elute at the same time on one method.
Chain of custody, and where it begins
The condition on arrival is recorded by some services and not others, and it is one of the more informative lines in a report.
What a laboratory knows about the material it receives
The condition on arrival is recorded by some services and not others, and it is one of the more informative lines in a report.
We split six vials four ways and posted them
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.
Six words a verification badge would need to mean anything
What a verification mark would have to carry to be checkable: a date, a lot, a method, a submitter and a link to the report.
Two decimal places, one injection, no procedure
Chromatographic purity is cheap, fast and comparable-looking. Those three properties, and not its usefulness, explain why it became the industry’s single figure of merit.
The badge economy, and what it is actually certifying
Lot-level verification with a public report is a real and achievable thing. It exists in this market, on a minority of listings.
Who chose the vial that was tested?
What a laboratory can and cannot know about the provenance, storage history and representativeness of what lands on its bench.
A named analyst is the cheapest quality signal in this trade
Two signatures — one who performed the work, one who approved its release — are the ordinary regulated convention and are almost unknown here.
The certificate says 2025. The vial in your hand does not say anything.
The interval between manufacture and analysis is the most under-read figure on the page, and the one most likely to matter by the time a vial is opened.
What a split-sample exercise can establish, and what it cannot
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 software decides what counts as a peak
Baseline placement under a tailing peak is a judgement call with a direct effect on the area. It is one of the few places where two competent analysts genuinely disagree.
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.
What column temperature does to selectivity
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.