A Certificate of Analysis (COA) is the per-lot analytical record for a material. It documents what was measured for that specific production lot, so it is tied to the lot number printed on the vial rather than to the product in general.
What it reports
A typical peptide COA lists identity (mass spectrometry confirming the expected molecular mass), purity (a percentage from RP-HPLC peak-area analysis), net content, and appearance. Some add water content or counterion data.
How to use it
Match the lot number on your vial to the lot on the COA — they must agree. Check which method produced the purity figure and confirm the identity result corresponds to the compound you ordered. For the analytical background, see peptide purity: RP-HPLC and ESI-MS.
Verifying a lot
You can look up the Certificate of Analysis for a lot at the lot verifier.
For laboratory research use only. Not for human or veterinary use, and not intended to diagnose, treat, cure, or prevent any disease.