Quality records · 5 min read
How to read a peptide Certificate of Analysis
A field-by-field guide to identity, purity, lot, method, and release information in a laboratory COA.
Start with identity
Confirm the material name, catalog identifier, lot number, and reported molecular information match the vial and purchase records. A COA should connect a specific result to a specific lot rather than describe a product generally.
Separate identity from purity
Identity testing asks whether the detected material matches the expected analyte. Purity testing estimates the relative proportion represented by the target peak under the stated method. These are distinct questions and should be documented separately.
Read the method and result together
A result is most useful when the analytical method, units, acceptance criteria, date, and reviewer are clear. RP-HPLC and mass spectrometry report different attributes; neither label alone explains the complete test conditions.
Preserve the audit trail
Store the COA with the receiving record, vial label, lot number, and internal experiment identifier. Record any discrepancy before material is released into a laboratory workflow.