Peptide COA Checklist: What to Verify Before Ordering

A peptide certificate of analysis (COA) is a record of reported test results for an identified sample or batch. This peptide COA checklist helps you organize a document review before ordering research material. It is a purchasing-record aid, not a substitute for your laboratory's acceptance procedures or an analyst's interpretation.

The useful question is not simply “Is the purity number high?” Ask whether the report matches the material, what each method measured, and which questions remain unanswered.

1. Match the document to the material

Record the product name, catalog code, lot or batch identifier, report number, issuing laboratory, and analysis date. Compare them with the product and order information available to you. When material arrives, check the label against the report again.

A representative report can illustrate a supplier's documentation format, but do not file it as evidence for a different lot. If a supplier uses a separate sample or repackaging identifier, ask for the documented link rather than assuming the numbers should match.

Suggested review note: “Lot linkage confirmed” or “Awaiting explanation of sample-to-lot mapping.” Keep the original document and the supplier's response together.

2. Separate purity, identity, and peptide content

These fields answer different questions. Bachem's peptide analysis FAQ distinguishes HPLC purity from net peptide content and gross sample weight.

• HPLC purity: A peak-area percentage describes relative detector response under the stated chromatographic conditions. It is not automatically the percentage of the vial's total weight occupied by the target peptide.

• Identity-related results: Read the named method, expected value, observed result, and acceptance basis together. Do not turn a reported mass match into claims about every structural feature.

• Net peptide content: This is separate from chromatographic purity. Counterions and residual water can contribute to gross sample weight; net peptide content also includes peptidic impurities.

For a fuller explanation of method limitations, see our HPLC and LC-MS document-reading guide.

3. Read the result beside its method and criterion

For each test, capture the method reference, result, units or calculation basis, and stated acceptance criterion. Ask for relevant supporting chromatograms, spectra, or method details when they are needed for your review. A summary certificate and the underlying analytical records are different documents; missing attachments are a reason to request information, not proof that the reported result is false.

Do not invent a universal 98% acceptance rule. Bachem's quality-control guide describes multiple product grades and application-dependent purity needs. Its examples also show why identity, purity, water, and residual-solvent measurements involve different analytical questions. Your laboratory should define the relevant specification for its intended research.

Illustrative example: If a report states 97.6% against a specification of at least 95%, that result meets that stated numerical criterion. It does not establish that the material meets a separate 98% requirement or that unlisted tests passed.

4. Record limitations and unresolved questions

Check the analysis date and any stated retest or expiry date alongside the applicable storage information. A date alone does not establish the present condition of material. Ask the supplier to explain missing or inconsistent information.

List application-relevant tests that are absent. Do not infer sterility, endotoxin results, biological activity, or suitability for human use from an HPLC percentage or identity result.

If accreditation is claimed, verify the laboratory and relevant scope with its accrediting body. ISO/IEC 17025 addresses laboratory competence; a logo by itself is not verification of a particular report or product. Do not assume that a different company name proves independence.

5. Keep a clear follow-up record

Use these questions to organize a request:

• Which current lot does this report describe?

• How does the sample identifier connect to that lot?

• What method and acceptance criterion support each result?

• Are the supporting analytical records available?

• Which requested attributes were not tested or not reported?

• What remains unresolved before our laboratory can make its acceptance decision?

Download our documentation review checklist to keep those notes in one place. For a Bio Peptides Labs product, request the available lot documentation with the exact product and lot details. This article does not claim that every product has every test described above.

Research-use boundary: Bio Peptides Labs products are for laboratory research only, not for human or veterinary consumption. Educational references do not certify our products or replace product-specific records.