Start with sample identity

A useful Certificate of Analysis should identify the tested material, batch or lot number, test date, laboratory and analytical method. The batch shown on the report should correspond with the identifier on the research product.

Separate identity from purity

Purity describes the proportion of detected material represented by the main analytical peak under a defined method. Identity asks whether that material is the compound claimed. These are related but separate questions, which is why laboratories may use chromatography for purity and mass spectrometry for molecular identity.

Check the method and supporting detail

Review the method name, sample identifier, reported result, chromatogram or spectrum, analyst authorization and any stated limitations. A single percentage without batch traceability or method information provides less context than a complete report.

Research use only. Analytical documents should be interpreted within the scope of the stated test.