Research Library · Methods Guide
How to Verify Research Peptide Purity
When sourcing research compounds, the label claim means little on its own: verification comes from a batch-specific certificate of analysis backed by independent third-party testing. This guide, written for laboratory researchers, explains what to check and the red flags to watch for. For research use only.
For Research Use Only. Not for human or veterinary use. Not a drug, food, or cosmetic. This page is educational reference material for qualified researchers and contains no medical advice, dosing, or health claims.
Trust the COA, Not the Claim
A legitimate certificate of analysis is batch-specific and answers four questions: identity, purity, concentration, and contamination. A generic "sample" or "typical result" document proves nothing about the vial in hand. The lot or batch number printed on the COA must match the lot on your vial, or the document describes different material.
For a section-by-section walkthrough of the document itself, see how to read a certificate of analysis.
The Two Tests That Matter
HPLC quantifies how much of the target compound is present, reported as a purity percentage. Mass spectrometry confirms identity by measuring molecular mass and comparing it to the expected value. Both are required: HPLC alone leaves identity unverified, and MS alone leaves purity undocumented. Research-grade standards typically look for at least 99% HPLC purity.
The methods are compared in detail in HPLC vs mass spectrometry in peptide testing.
Red Flags
- An unnamed "third-party lab" with no identifiable accredited laboratory behind the document.
- HPLC-only COAs with no mass-spectrometry identity confirmation.
- No batch or lot number, or a lot number that does not match the vial.
- No way to independently verify the document against the supplier's records.
How AurexBioLabs Handles It
Every AurexBioLabs compound is third-party HPLC and mass-spec tested, and each batch's COA is downloadable and independently verifiable at our COA verification page. Laboratory preparation of lyophilized material, including diluent choice, is covered in the peptide reconstitution guide, and the bacteriostatic water listing documents the diluent itself.
Frequently Asked Questions
A batch-specific document confirming a compound's identity, purity, and analytical fingerprint, listing the peptide name, sequence, batch/lot number, purity %, testing methods, and issuing lab.
The COA should name a specific, identifiable laboratory (not an anonymous "third-party lab") and provide a way to independently confirm the result. AurexBioLabs COAs are verifiable at aurexbiolabs.com/verify.
Research-grade standards typically look for at least 99% purity by HPLC, shown as a numeric percentage alongside the chromatogram.
HPLC tells you how pure the sample is; mass spec tells you what the compound actually is. Together they confirm both purity and identity.
A generic or sample COA with no matching batch/lot number, or "third-party tested" language with no named, verifiable laboratory.
Next Steps
Verification & catalog
For Research Use Only. Not for human or veterinary use. Not a drug, food, or cosmetic. This page is educational reference material for qualified researchers and contains no medical advice, dosing, or health claims.
For Research Use Only. Not for human or veterinary use. Not a drug, cosmetic, or dietary supplement. All information is provided for laboratory research purposes only.