How to Read a Peptide Certificate of Analysis
How to read a research peptide certificate of analysis: HPLC purity, mass spectrometry identity, batch numbers and what to check.
A certificate of analysis (COA) is the document that links the vial in your hand to the analytical data behind it. Knowing how to read one is the fastest way to evaluate a peptide supplier.
HPLC — purity
High-performance liquid chromatography separates the target peptide from impurities such as truncated or deletion sequences. Purity is reported as the main peak's share of total peak area. Port Peptides specifies ≥99% for research peptides.
Mass spectrometry — identity
MS confirms that the observed molecular mass matches the theoretical mass of the sequence. A matching mass, together with a clean HPLC trace, gives confidence you have the right molecule.
What to check on every COA
- Batch or lot number that matches your vial label.
- Product name, sequence and molecular formula.
- Test date and the method used.
- HPLC chromatogram and MS spectrum, not just a single number.
Request the COA for any product via our contact page, or read more about our quality process.
