Peptide Assay vs HPLC Purity: Why Content Is a Separate COA Question
HPLC purity can describe the relative area of the main peptide peak, but it does not always tell you how much target peptide is present by mass. Peptide assay, net peptide content, moisture, counterions, and method validation all shape the bigger quality picture.
Jul 18, 2026
Research Use Only COA Literacy
Peptide Assay vs HPLC Purity: Why Content Is a Separate COA Question
A strong COA separates chromatographic purity, identity, and actual peptide content instead of forcing one number to explain everything.
Research Use Only Disclaimer
BetterBio Synthesis materials and educational content are intended for laboratory research use only. This article is not medical advice, does not recommend human or animal use, and does not provide dosing, administration, treatment, cure, or efficacy guidance. Any peptide, compound, or research material discussed here should be evaluated only by qualified professionals in appropriate research settings and in accordance with applicable laws, institutional requirements, and safety protocols.
A peptide Certificate of Analysis can look simple from a distance: product name, lot number, purity percentage, mass confirmation, and a few supporting fields. But one of the easiest mistakes in COA review is treating every percentage as if it answers the same question.