Identity (mass spectrometry)
Mass spectrometry confirms the molecular weight of the peptide. The measured mass should match the expected (theoretical) mass for the sequence — this verifies you received the correct compound.
Purity (HPLC)
High-performance liquid chromatography (HPLC) separates the sample into its components and reports purity as a percentage of the main peak. A higher percentage means fewer impurities. Look for the purity figure and the chromatogram showing a clean dominant peak.
Net peptide content
The labeled mass of a vial includes counter-ions, residual water, and salts in addition to the peptide itself. Net peptide content describes how much of the total mass is actually peptide — useful when precise quantities matter for an experiment.
Lot and traceability
Match the lot number on the COA to the lot on your vial. The COA describes the specific batch you received, not a generic product — keeping them paired preserves traceability.