The four things every COA should show
- Product name and lot/batch number
- Test date and the lab that ran it
- HPLC purity percentage with the chromatogram
- Mass spec result showing observed vs. expected molecular weight
Reading HPLC
HPLC separates a sample into components. The tall main peak is your peptide; small peaks are impurities like truncated sequences. Purity is the main peak's area as a percentage of the total.
Reading mass spec
Mass spectrometry measures molecular weight. If the observed mass matches the theoretical mass of the sequence, identity is confirmed. Purity without identity tells you a sample is clean — not that it's the right molecule.
What a COA doesn't tell you
Standard purity and identity tests do not measure sterility, endotoxins or heavy metals. Those require separate tests. Never treat a purity number as a safety claim.
Frequently asked questions
- What purity is good for research peptides?
- The acceptable analytical specification depends on the laboratory protocol. Evaluate the method and batch-specific report; no universal purity threshold establishes suitability.
- Does HPLC prove a peptide is sterile?
- No. HPLC measures purity only. Sterility and endotoxin testing are separate assays.