How to read a peptide Certificate of Analysis (COA) — HPLC purity, mass spectrometry and sequence identity, and why batch COAs matter for research peptides.
A Certificate of Analysis (COA) is a document provided by a supplier that confirms the quality and purity of a specific batch of product. For research peptides, the COA typically includes results from analytical testing such as HPLC, mass spectrometry, and amino acid analysis. A COA provides objective evidence that a product meets its stated specifications.
Product identification (name, CAS number, batch number). HPLC purity data (percentage purity, typically ≥99%). Mass spectrometry results (molecular weight confirmation). Appearance and physical characteristics. Testing date and laboratory information. Any additional tests performed (endotoxin testing, solubility, etc.).
High-Performance Liquid Chromatography (HPLC) is the primary method for determining peptide purity. The HPLC chromatogram shows peaks corresponding to different compounds in the sample. The main peak represents the target peptide, and purity is calculated as a percentage of the total peak area. A purity of 99%+ means that at least 99% of the sample consists of the intended peptide, with less than 1% being synthesis-related impurities.
Mass spectrometry (MS) confirms the molecular identity of a peptide by measuring its molecular weight. The observed mass should match the expected theoretical mass within acceptable tolerances (typically ±0.1%). This confirms that the correct peptide sequence was synthesised. Electrospray Ionisation Mass Spectrometry (ESI-MS) is the most commonly used technique for peptide analysis.
Using peptides without verified purity can introduce confounding variables into experiments. A COA ensures that your research compounds meet the specified standards, improving reproducibility and reliability of results. When publishing research, reviewers and journals increasingly expect documentation of reagent quality, making COAs essential for credible scientific work.
At Neovia Peptides, Certificates of Analysis are available for every product we sell. COAs can be downloaded directly from the product page or requested by contacting our team at [email protected]. We provide batch-specific documentation to ensure you have the exact testing data for the product you received.
Research-grade compounds referenced in this guide, supplied with full Certificates of Analysis.
All products sold by Neovia Peptides are strictly for in-vitro research and laboratory use only. Not intended for human or veterinary use, food additives, drugs, or cosmetics. By purchasing from this website, you agree that you understand and accept these terms.
