A Certificate of Analysis (COA) documents the identity, purity and traceability of a peptide batch. Reading it critically is essential for reproducible research.
Purity by HPLC
Reversed-phase HPLC-UV at 220 nm quantifies relative purity. A value ≥99% means less than 1% of the sample corresponds to truncated, oxidized or synthesis impurities.
Identity by ESI-MS
Electrospray ionization mass spectrometry confirms molecular identity within a tolerance of ±0.1 Da between measured and calculated mass.
Additional parameters
- Acetate content: residual counter-ion from purification.
- Water and residual solvents: influence stability.
- Endotoxins: relevant for cell-culture and in vivo work.
- Appearance: amorphous white powder is expected.
Traceability
Every COA must reference a unique batch code that links vial, analysis and shipment. Peptide Life batches can be verified publicly.