The Two Tests Every Peptide COA Needs
A trustworthy Certificate of Analysis (COA) for a research peptide includes two independent tests: HPLC for purity percentage and mass spectrometry for molecular-weight confirmation. HPLC alone can’t prove you have the right peptide — it only shows how pure whatever-you-have is.
The common scam is a vendor that prints “HPLC 99%” on a datasheet with no mass spec, or a mass spec that was clearly run on a different batch. Learning to read both is the single highest-value skill for anyone sourcing peptides.
HPLC vs Mass Spectrometry — What Each Proves
- HPLC: purity percentage and impurity profile — how clean the material is
- Mass Spectrometry: confirms the measured molecular weight matches the expected sequence — what the material actually is
- Amino Acid Analysis: verifies the residue composition of the full sequence
- Together: they answer “how pure” and “is it the right compound”
Red Flags in a Peptide COA
Reject any COA that lists purity without a matching mass-spec trace, shows a different molecular weight than expected, or can’t be tied to your specific batch number. A COA that isn’t batch-specific is just marketing.
FAQ
What purity should a research peptide be?
Accept ≥98% HPLC purity as the research-grade standard. Material below 97% suggests incomplete purification.
Is mass spec more important than HPLC?
They answer different questions — HPLC measures purity, mass spec confirms identity. A genuine COA needs both.
What if a supplier won’t share a COA before purchase?
That’s a red flag. Legitimate suppliers share batch-specific COAs on request.
Important: All products are sold strictly for laboratory and research purposes only — not for human or veterinary use. No medical or dosing guidance is provided.