What Is a COA?
A Certificate of Analysis is a document issued by a testing laboratory that reports the results of quality testing performed on a specific batch of product. For research peptides, a COA typically includes purity data (HPLC), identity confirmation (mass spectrometry), and physical characteristics of the tested batch.
The COA is the primary quality document in the peptide supply chain. It provides objective, third-party evidence that the product meets its specifications. Without a COA, you are relying entirely on the supplier's word.
What a COA Should Include
Batch/Lot Number: A unique identifier that links the COA to a specific production batch. This number should match the label on your vial.
Product Name and Sequence: The peptide name and amino acid sequence, confirming what was tested.
HPLC Purity: The purity percentage determined by HPLC, ideally accompanied by the actual chromatogram image.
Mass Spectrometry: The observed molecular weight compared to the expected molecular weight, confirming identity.
Appearance: Physical description of the product (typically white to off-white lyophilized powder).
Testing Laboratory: The name of the laboratory that performed the analysis. Third-party testing is preferable to in-house testing.
Date of Analysis: When the testing was performed.
Red Flags in COAs
Watch for COAs that lack a unique batch number, show identical results across different batches, do not include actual chromatogram or spectrum images, reference unnamed laboratories, or show dates that are years old. These may indicate generic template COAs rather than actual batch-specific testing.
Verifying Authenticity
A genuine COA will have specific, non-round numbers (e.g., 99.23% rather than exactly 99.0%). The chromatogram should show realistic baseline noise and peak shapes. The molecular weight should match published values for the peptide within 1 Da. If anything looks templated or too perfect, ask the supplier for clarification.
