How to Read a Peptide COA: Lab Report Examples and Checklist
A peptide Certificate of Analysis (COA) is useful when its results can be traced to the material being evaluated. Start with the lot number, then ask which properties were measured, how they were measured and what the results actually establish. This guide is the starting point for reviewing peptide lab reports.
For Research Use Only. Not for human or veterinary use.
A peptide COA review checklist
- Match the material: compare the compound name, variant, salt or modification where stated, and lot number with the label and purchasing record.
- Identify the report: record the testing laboratory, report number, test date and document revision where provided. Resolve a missing or mismatched identifier with the supplier.
- Read each test separately: note the method, result, units and applicable specification. “Pass” without a defined test or criterion needs clarification.
- Inspect supporting evidence: look for chromatograms, spectra or other data supporting the stated results, and request clarification where interpretation is unclear.
- Record the limits: mark attributes that were not tested rather than assuming that an omitted test passed.
Purity, identity and content answer different questions
Chromatographic purity commonly describes the main peak’s share of the detected, integrated peak area under a particular method. It does not independently establish the quantity of target peptide in a vial. Bachem’s quality-control guide distinguishes this measurement from peptide content and from water, counterions and residual solvents.
Identity testing asks whether the observations support the stated material. An intact-mass result supports a molecular-mass comparison; it should not automatically be described as complete sequence confirmation. See the dedicated peptide identity and sequence verification guide for that distinction.
Three illustrative lab report examples
These examples are hypothetical review situations, not Vertex batch results or acceptance specifications.
| Report shows | What you can conclude | What to clarify |
|---|---|---|
| A lot number and HPLC purity result | A chromatographic purity result is reported for the identified sample. | Which identity test was performed? Is supporting chromatographic data available? |
| HPLC purity plus observed molecular mass | The report adds evidence about molecular mass to the purity result. | Does the identity evidence resolve the particular variant or modification being evaluated? |
| Purity, identity and a separate quantitative content result | The document reports additional information about the amount or concentration measured. | What are the units, sample basis and quantitative method? Does the result refer to a vial or a submitted portion? |
Which additional tests matter?
Endotoxin, sterility, residual solvents, elemental impurities, stability and functional activity are separate questions. A purity number does not establish results for these attributes. Choose additional documentation according to the research method and the laboratory’s acceptance criteria; there is no single analytical panel that answers every research question.
A stated minimum purity is a specification, while a batch result is a measurement. Keep both in the record and compare them directly. Do not substitute a brand-wide claim for the actual lot report.
Before accepting the documentation
If the lot does not match, request the correct document before treating it as evidence for your material. If a result lacks units or a method, request an explanation. A third-party laboratory provides an additional source of analytical evidence, but its name alone does not establish accreditation, sample provenance or the scope of testing.
Keep a copy of the report and your review notes with the purchasing record. When a revised report arrives, retain the revision history. For hazard and handling information, consult the appropriate SDS as well; our COA vs SDS guide explains the different roles.
Find Vertex batch documentation
For a single-compound example, review the BPC-157 presentations and linked batch documentation. Check both the labeled vial amount and lot number; a certificate linked to one presentation should not be applied to another.
To compare how product identity and presentation connect to batch documentation, review the KLOW blend product and COA and the MOTS-C product presentations and COAs. Match the exact material and lot before interpreting a report; a result for one blend or presentation does not verify another.
Use the Vertex COA library to locate available reports and compare their lot identifiers with your material. Review testing standards alongside the actual report. Only attributes documented as tested for that lot should be treated as measured results.
References
- Bachem: Quality control of amino acids and peptides — identity, chromatographic purity, peptide content and residual components.
- Recommendations for the generation, quantification, storage and handling of peptides used for mass spectrometry-based assays — recommendations developed for peptide standards in mass spectrometry workflows, rather than a universal specification for every research material.