COA (Certificate of Analysis)
The Certificate of Analysis (COA) is the quality document accompanying each commercial peptide batch. It documents the analytical control results performed by the manufacturer to attest product compliance with manufacturing specifications. For a researcher, the COA is the reference document before any experimentation: it verifies identity, purity, molecular mass, and storage conditions of the received peptide. Without rigorous traceable COA, research loses all scientific reproducibility.
A standard peptide COA contains at least nine critical fields. The full chemical name and sequence in one- or three-letter code unambiguously identify the molecule. The batch number traces production and enables linking any future defect to the concerned manufacturing cycle. The gross molecular formula (C, H, N, O, S) and the theoretical monoisotopic molecular mass serve as calculation references. HPLC purity, expressed as percentage, is the central parameter: Lab Peptides France peptides typically display >98%. The mass observed by mass spectrometry must match theoretical (deviation <0.1%). Physical appearance (white powder, lyophilized cake) confirms product state. Residual water content by Karl Fischer titration (typical <5%). Endotoxins by LAL test (<10 EU/mg for demanding in vivo research). Recommended storage conditions (temperature, light/humidity protection, shelf life).
Premium COAs include additional data for high-rigor research. The printed HPLC chromatogram enables direct visualization of impurity distribution around the main peak. The ESI or MALDI mass spectrum visually confirms observed mass and charge state. Elemental analysis (C, H, N) and active peptide titration (for acetate or TFA salts) measure the real net peptide fraction. Some advanced COAs add residual solvent analysis (DMSO, acetonitrile, DMF) by gas chromatography, TFA content determination (key biological test: TFA <5% is acceptable, <1% ideal), and degradation profile after accelerated stress (48h at 40 C).
To interpret a COA, the researcher must verify three essential points. First, that observed mass matches theoretical mass within 0.1% — greater deviation signals synthesis error or contamination. Second, that HPLC purity is appropriate for use: >95% for in vitro cellular tests, >98% for in vivo experiments, >99% for chronic studies or fragile populations. Third, that COA date is recent (under 12 months) and that specified storage conditions were respected during transport and warehousing.
An authentic, complete, and traceable COA distinguishes professional suppliers from opaque sources. It also constitutes legal and scientific protection: in case of experimental result anomaly, the COA enables tracking back to source and eliminating defective batch hypotheses. At Lab Peptides France, available COAs are published on the relevant product pages; our Janoshik reports carry a verification key to enter on janoshik.com. This rigorous documentation is the basis of trust between manufacturer and researcher.