Encyclopedia entry

Certificate of Analysis (CoA)

A CoA is a document from a third-party analytical lab confirming the purity, identity, and (depending on scope) additional properties of a chemical sample. For research peptides, the minimum is a CoA covering HPLC purity and mass-spectrometry identity. UK retailers either include the CoA with each order or make it available on request.

What a strong CoA covers

• · The molecule\'s identity, confirmed by mass spectrometry.
• · Purity percentage by HPLC, with the gradient and method documented.
• · Batch or lot number, linked to the physical vial.
• · Date of testing and lab name.
• · Optionally: endotoxin (for human-grade material), heavy-metals testing, residual solvents.

What a CoA does not prove

• · Sterility (separate test, usually direct culture).
• · Biological activity (no analytical proxy; activity is established in cell or animal models, not in vials).
• · That this specific vial is the one the CoA describes (only batch traceability links them).
• · Long-term storage stability (a separate stability test).

Provided-with-order vs on-request

Provided-with-order CoA arrives in the package or by email automatically; the customer does not need to ask. On-request CoA is sent if the customer emails the retailer, typically within 1 to 3 working days. Either is acceptable. Provided-with-order is the higher-confidence default and scores higher in editorial ranking.

Related: HPLC purity · UK research peptide retailers.