Reading a COA.

A certificate of analysis, COA for short, is a laboratory's report on one specific batch. It is not a seal of approval and not an endorsement. It is measurements, and you have to judge them yourself.

The header

At the top are the details that tie the report to your vial: the name of the compound, the batch or lot number, the date of analysis and the name of the laboratory. If the batch number is missing, you cannot verify that this report belongs to your batch.

The chromatogram

The HPLC chromatogram is a graph with one large peak and usually a few small ones. The horizontal axis is time, the vertical is signal strength. The main peak is the target compound, the small peaks are related compounds.

Below the graph is a table with the retention time and the area percentage per peak. The number at the main peak is the purity quoted on the front.

The mass spectrum

Next to it there should be a mass spectrometry analysis. It gives the measured molecular mass alongside the theoretical mass of the compound. If they are close together, the identity is confirmed.

What is often missing

• Heavy metals. Often left out because it is a separate measurement.
• The name of the lab. A report without a sender cannot be verified.
• The batch number. Without that link it is a generic leaflet.
• The test date. A report from 2022 with a batch from 2026 does not add up.

A red flag

Exactly 99.9 percent for every product and every batch is statistically unlikely. Real measurements vary. A series of identical results points to a template rather than a measurement.