Definition
A batch-specific document reporting the analytical test results that confirm a peptide's identity, purity and quality.
A certificate of analysis documents the testing performed on one production batch. A complete peptide COA lists the product name, sequence, molecular formula and theoretical molecular weight, the batch number, test and manufacture dates, the testing laboratory and an authorising signature. Core results are HPLC purity with the chromatogram attached, and mass spectrometry identity with observed and theoretical masses. Additional results may include counter-ion, net peptide content, water content and endotoxin. The batch number on the COA must match the vial label. Warning signs include a purity figure with no supporting data, a reported purity of exactly 100%, and the same document reused across batches.