COA and Testing
How certificates of analysis, HPLC purity, identity, endotoxin and lot traceability work for research peptides.
Articles in COA and Testing
- Research noteCOA and Testing
Peptide Purity vs. Net Content: Understanding the Difference
HPLC purity is the main peak's share of total peak area: it says how much of the detected peptide material is the target compound. Net peptide content is the mass of peptide in the vial, measured against a reference standard and compared with the label claim. Counter-ions, water, residual solvent and fill mass change content without changing purity, which is why a 99.99 % pure lot can measure 9.22 mg in a 10 mg vial and another lot 58.15 mg in a 50 mg vial.
November 7, 2026 - Research noteCOA and Testing
How to Read a Peptide Certificate of Analysis (COA)
A peptide certificate of analysis reports what an independent laboratory measured on one sample of one lot: identity, chromatographic purity, net content against the label claim, the methods used and the specifications applied. This guide explains each field using three genuine Precise Pep Labs certificates, and shows what a purity percentage can and cannot tell you.
November 6, 2026