Check a certificate of analysis

Paste what a certificate claims and this page checks it. It compares the stated molecular weight against a reference value from PubChem, looks for the fields a certificate needs, and flags the figures that are usually wrong. It works on any supplier’s certificate, including ours.

Nothing you type leaves your browser. There is no upload, no account, and no limit on how many certificates you check.

Compound Select…

Molecular weight stated In g/mol or Da, as written on the certificate

Purity stated, %

Issuing laboratory The name on the document

Accreditation stated For example ISO/IEC 17025

Lot or batch number

Test date Any readable date, for example 2026-03-14

Methods stated For example RP-HPLC and LC-MS

Check this certificate

What this checks, and what it cannot

The molecular weight check is the part other tools leave out. A certificate can carry every heading a checklist asks for and still state a mass that is wrong for the compound named on it. This page compares the figure given against the reference value, and recognises the salt forms — trifluoroacetate and acetate — that legitimately shift a synthetic peptide’s mass, so a correct certificate is not failed for being correct.

It cannot tell you a document is genuine. Anyone can type a laboratory’s name onto a page. The only way to settle that is to contact the laboratory with details you found yourself and ask them to confirm the report.