Editorial standard
The testing standard we hold vendors to
We do not manufacture, sell, or ship anything, so we have no batches of our own to defend. What we have is a rubric. This is the analytical panel we expect a vendor to publish per batch, and what a missing panel tells you. It is the same rubric behind every vendor score on this site.
An independent laboratory, named on the document
Self-reported purity is not third-party testing. The certificate should carry the analysing laboratory's name, a report number, and enough identity that you could contact them. An unbranded template with no laboratory on it is a self-test with extra steps.
HPLC at 220 nm, with the chromatogram shown
Reverse-phase C18 with UV detection at the peptide-bond wavelength, and the raw trace published rather than a bare percentage. The trace is where a wide peak concealing shoulder impurities is visible. We treat a summary figure with no chromatogram as unverified.
Mass spectrometry for identity
ESI mass spectrometry confirming observed molecular weight against theoretical, within the instrument's stated tolerance. Purity answers how much of one substance is present. Only mass spec answers which substance it is.
Endotoxin, reported in EU/mg
The most frequently omitted panel in this market, and the one that matters most for anything cell-based downstream. Endotoxin is heat-stable and survives sterile filtration, so a chemically pure material can still carry it. A vendor who publishes everything except this has usually made a choice.
Residual solvent screening
A GC panel covering TFA, acetonitrile, and other synthesis-stage solvents, reported per batch. It matters for two reasons: solvent displaces peptide mass against the labelled weight, and residual TFA is active enough to interfere with sensitive assays.
Batch numbering you can actually trace
Every analytical result belongs to a synthesis run, not to a product line. A vial identifier should resolve to a dated certificate for that exact run. One certificate published under a product name, with no batch traceability, is a sample of the vendor's best day.
Certificate archive lookup
We keep certificates we have collected and reviewed on file, indexed by batch number. Enter a batch number from a certificate or a vial label to see whether it is in the archive and what the analysis returned.
Not finding a batch here is not a finding against it. The archive only covers documents that have reached us. If you have a certificate worth adding, send it over.
Reading a certificate yourself
The rubric above is what we check. The checklist walks the same ground in the order the panels appear on a real document, with the failure mode next to each one, so you can run it on whatever a vendor sends you.