Purity & certificates
Every batch, and what the laboratory found
Identity and purity determined by RP-HPLC at an independent laboratory, against a reference standard. We publish the certificate as it was issued — the full document, not a summary of it.
This batch is at the laboratory. Its certificate is published here the moment it is issued.
Certificates without a matching product
These certificates were issued for presentations we do not currently sell. They are published anyway, because hiding an analysis is not something a purity page should do.
How this is measured
Identity is confirmed by ESI-MS: the measured mass must fall within ±2 Da of the theoretical mass. A peptide with the wrong sequence fails here before anything else is tested.
Purity is determined by RP-HPLC with UV detection at 220 nm, the wavelength where the peptide bond absorbs. The figure is the area of the main peak as a percentage of the total.
System suitability (USP <621>) is run before every batch: if the column is not resolving properly, the purity number means nothing. That is why those four parameters appear on every certificate.
Research use only. These certificates describe the material in the vial — not what it does, and not what it is for. We make no recommendation for human use.