A COA is only useful if the numbers on it can be reproduced by your own laboratory. We have published the checklist our own release team uses when reviewing an incoming peptide certificate of analysis.
The five fields that matter
Batch number and date, purity with the HPLC method stated, MS identity confirmation, moisture or water content, and residual solvent results. A signature alone is not evidence of any of them.
Request a redacted sample COA and compare it with your incoming-goods specification before your next audit cycle.