How To Read a Certificate of Analysis

A Certificate of Analysis (COA) is the primary quality document that accompanies a research chemical. For synthetic peptides, a well-formed COA reports the identity, purity, and physical properties of a specific manufactured lot and links those results to defined analytical methods. Reading a COA critically is a core competency for any laboratory that purchases peptide reference materials for in-vitro research.

A COA may report identity testing, often using mass spectrometry; review the method and results for the specific lot. Electrospray ionization (ESI-MS) or MALDI-TOF results should show an observed monoisotopic or average mass that matches the theoretical mass of the target sequence within the instrument's stated tolerance. A COA that lists a molecular weight without an accompanying spectrum or a stated instrument tolerance provides weaker evidence of identity than one that documents both.

For distinct catalog context, not equivalent study preparations, see BPC-157 10MG.

Purity is typically reported by reverse-phase HPLC at a defined wavelength, most commonly 214 nm for the peptide bond or 280 nm when aromatic residues are present. The COA should state the column, mobile phase gradient, and detection wavelength alongside the numeric purity value. A purity claim expressed only as a single percentage - with no chromatogram and no method description - should be treated as unverified.

Beyond identity and purity, a complete COA reports water content (often by Karl Fischer titration), residual solvent content (by gas chromatography), acetate or trifluoroacetate counterion content when relevant, and appearance. For peptides intended for cell-culture research, endotoxin testing by the LAL method may also appear. Each of these values has an accepted method described in the United States Pharmacopeia or the ICH Q6A specification framework, and a credible COA cites the method it followed.

Lot traceability is the final piece. Review any lot identifier, manufacture date, retest or expiration information and issuing-laboratory details, and confirm what the documentation supports. Retain the COA alongside your inventory record; when an experimental anomaly arises months later, the ability to trace a result back to a specific lot and its release data is often what separates a resolvable question from an unresolvable one.

For a catalog example of compound identity, see BPC-157 catalog identity details. This link is not a lot report or evidence of testing. For analytical context, see the guide to reading a certificate of analysis.

All materials described are for in-vitro laboratory research only and are not for human or veterinary use.