A peptide Certificate of Analysis, or COA, provides essential information about the identity, purity, composition, and quality of a peptide batch. Understanding these results can help researchers determine whether a product meets their project requirements.
Peptide Purity
Purity is commonly measured by HPLC and reported as a percentage. A result such as 98% indicates that the target peptide represents approximately 98% of the detected chromatographic material. However, HPLC purity does not always equal the actual peptide content by weight.
Molecular Weight
Mass spectrometry is used to confirm the molecular weight of the peptide. The measured value should closely match the theoretical molecular weight calculated from the peptide sequence and any modifications.
Peptide Content
Net peptide content shows how much active peptide is present in the total material. The remaining weight may include water, counterions, residual salts, or other non-peptide components. This value is especially important when preparing solutions based on precise peptide quantities.
Counterions and Water Content
Peptides may be supplied as acetate, trifluoroacetate, or other salt forms. The COA may also report water content, which can affect the total weight and concentration calculations.
Batch and Testing Information
A complete COA should include the product name, sequence, batch number, test methods, results, manufacturing date, and storage recommendations. These details support batch traceability and help customers review product consistency.
Understanding a peptide COA involves looking beyond a single purity number. Identity, molecular weight, peptide content, counterion form, and analytical methods should all be considered when evaluating a peptide batch.
For laboratory research use only. Not intended for human or veterinary use.