How to Read a Certificate of Analysis (COA)

A Certificate of Analysis (COA) is the analytical record for a specific production batch. It documents what testing was performed and what the results were, so a receiving lab can verify identity and purity before material enters a workflow.

The fields that matter

• ✓Compound identity & sequence — confirms the material matches what was ordered
• ✓Measured purity — the analytical purity value, with the method used (e.g. HPLC)
• ✓Molecular formula & mass — supports identity confirmation, often via mass spec
• ✓Batch / lot number — ties the document to the exact vial you received
• ✓Test date — when the analysis was run
• ✓Supplied form & storage — how the material was prepared and should be kept

Batch-specific beats generic

The single most important quality of a COA is that it's tied to your lot. A generic sheet that could apply to any batch tells you little. A batch-specific COA — with a lot number that matches your vial — is what supports genuine receiving and recordkeeping.

Red flags

• ✓No analytical method named next to the purity figure
• ✓No batch/lot number, or one that doesn't match the vial
• ✓A headline purity claim with no supporting document at all