How to read a peptide certificate of analysis

1. Match the certificate to the sample

Start with the laboratory name, Report ID, sample description, lot or batch identifier and relevant dates. Compare them with your own records. If the lot is missing or differs, ask for clarification before treating the report as evidence for that material.

• Keep the full certificate, including any supporting pages or limitations.
• Distinguish the client’s stated compound or label claim from the laboratory’s measured finding.
• Check whether a sample identifier was recorded by intake or supplied by the client.

2. Identify what each result measures

HPLC area percentage describes a relative detector signal under the stated chromatographic method. An identity finding supports a comparison with the expected material. A content assay reports an amount or concentration on a defined basis. The NIST peptide reference-material certificate linked below reports UV area purity and peptide mass purity separately.

Look for a method name, a numerical result where appropriate, the units and any comparison limit. A percentage without its reporting basis is incomplete information.

• Purity: what detector and integration basis produced the percentage?
• Identity: what comparison and evidence support the conclusion?
• Content: is the result a mass per vial, concentration or mass fraction?

3. Read the method and any qualification

Read the chromatogram or spectrum with the reported method, rather than assessing its appearance alone. Ask the laboratory to explain an unexpected peak, an unreported analysis or a qualified result. A method should be suitable for the question and material being tested.

An analysis that was not performed has no result to infer. A purity measurement does not substitute for a separately requested contaminant or microbiological test, and the COA does not establish suitability for medical use.

4. Check the live record

Verify a Pepper Tester Report ID against the source record and compare the revision with your document. Where a private certificate requires a secure link or access key, obtain it from the authorized report holder. If anything differs, contact the laboratory with the report number and the document you received.

Verification confirms the report record. It does not demonstrate that another vial, another shipment or every item in a batch was represented by the submitted sample.

Further reading and sources

• NIST RM 8327 certificate: separate UV area purity and peptide mass purity results
• FDA / ICH Q2(R2): analytical specificity, selectivity and intended purpose