How to Spot a Fake or Recycled Certificate of Analysis

Because the Certificate of Analysis is the document buyers look to for reassurance, it is also the document most worth faking. There are two common failure modes. A recycled COA is a real certificate from one batch presented as if it covers a different, untested batch — the data may be genuine but it does not describe the vial you received. A fabricated COA is a document with no real testing behind it: a plausible-looking graphic assembled to satisfy a buyer who is unlikely to scrutinize it.

Both defeat the purpose of a COA, and both are detectable if you know what genuine certificates contain.

The first and most decisive check is the batch or lot number. A genuine COA describes one specific synthesis run and carries a batch identifier that matches the label on your vial. If the certificate has no batch number at all, or if the number does not match your vial, the document does not describe your material — full stop. This single check catches most recycled COAs, because a recycled certificate carries the batch number of the original tested run, not yours.

Be especially skeptical of a vendor that shows a single COA for a compound it has been selling for a long time. Purity is a property of each batch; one certificate cannot vouch for every run produced over months or years.

Genuine analytical reports have a characteristic anatomy. Look for an actual chromatogram and mass spectrum — the data plots — not just a summary table of numbers. Fabricated COAs often present clean-looking figures with no underlying traces, because generating convincing fake chromatograms is harder than typing a percentage into a template.

Other tells: no named testing laboratory, or a lab name that returns nothing when searched; a missing or implausible test date; method parameters absent (no column, gradient, or detection wavelength listed); mismatched fonts, misaligned tables, or low-resolution pasted images suggesting a document edited in an image editor; and a stated purity that the chromatogram, if present, does not visually support. Individually any of these can have an innocent explanation; together they are a pattern.

You do not need a lab to sanity-check a COA. Confirm that the molecular weight on the mass spec section matches the published molecular weight for that peptide's sequence — a mismatch means wrong identity. Search the named testing laboratory to confirm it exists and runs the methods cited. Check that purity and content are reported as distinct measurements rather than a single number doing double duty. And verify internal consistency: the compound name, batch number, and date should agree across every section of the document.

The structural defense against fake COAs is buying from a source that posts named, independent, per-batch certificates openly, so verification is built into the purchase rather than something you have to demand after the fact. When the real document is always available and always batch-matched, recycled and fabricated certificates have nowhere to hide.