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Certificates of Analysis

What Should a Research Peptide Certificate of Analysis Include? 12 Things to Check

A good research-peptide Certificate of Analysis (CoA) should be more than a purity percentage. It should connect a specific material to its batch, testing date, laboratory, analytical methods, and actual results. IDUN Peptides’ current CoA library provides batch-level documentation that can be searched by peptide, lot, laboratory, and testing method.

What Is a Research Peptide CoA?

A CoA is an analytical document associated with a particular material or production batch. It records what was tested and what the analysis found. Useful CoAs commonly include product identification, batch/lot traceability, testing date, laboratory, analytical methods, HPLC purity, chromatographic data, mass-spectrometry information, measured results, and report identifiers.

A document displaying a company logo and “99% purity” is not necessarily equivalent to a detailed, traceable analytical report.

1. Product or Compound Identification

The certificate should clearly identify the substance tested. Relevant information may include:

Compound or product name

Molecular formula and weight

Peptide sequence

Modifications

Salt or counter-ion

CAS number or another identifier

The goal is to make it clear exactly what material the reported results describe.

2. Batch or Lot Number

The batch/lot number links the analysis to a particular production run. Always compare:

CoA lot number → vial/package lot number → procurement record

A CoA for one batch does not automatically establish the characteristics of another. IDUN’s CoA library includes a Batch/Lot field for this reason.

3. Test Date

A test date establishes when the analysis was performed and helps connect the production batch, analytical report, supplier documentation, and laboratory records.

When comparing certificates, look at both the batch and testing date rather than comparing purity percentages alone.

4. Testing Laboratory

A useful certificate identifies the laboratory responsible for the analysis, where applicable. This improves traceability and lets researchers investigate the source of the analytical information.

The important question is not simply whether a supplier says “third-party tested,” but who actually performed the testing?

5. HPLC Purity Result

HPLC, or high-performance liquid chromatography, is commonly used to assess chromatographic purity by separating components in a sample.

If a certificate reports “≥99% HPLC purity,” also ask:

Is the chromatogram provided?

What method was used?

What does the percentage represent?

Is it linked to a specific batch?

Is identity addressed separately?

The percentage is useful, but its analytical context matters.

6. HPLC Chromatogram

A chromatogram provides visual evidence of the separation and can make a CoA considerably more informative.

Look for sample identification, retention information, the primary peak, additional peaks, analytical conditions, integration data, and the reported purity calculation.

You don't need to independently validate the chemistry to perform a documentation review. The objective is to determine whether actual analytical information supports the reported result.

7. Mass-Spectrometry Identity Information

HPLC purity and molecular identity answer different questions. Mass spectrometry can provide molecular-mass information supporting peptide identification.

A high HPLC purity result does not automatically prove every aspect of identity, while an identity result does not establish every possible quality characteristic. Complementary analytical methods therefore provide more useful documentation.

8. Expected vs. Observed Molecular Mass

Where mass-spectrometry data are reported, compare the expected molecular mass with the observed result. Depending on the method, the report may also show the analytical technique, charge state, spectrum, or relevant modifications.

Modifications, salts, and counter-ions can affect expected mass, so the molecular form being tested matters.

9. Analytical Method Details

A strong CoA should explain how the reported result was obtained. Examples include RP-HPLC, HPLC-UV, LC-MS, and LC-MS/MS.

Method information provides context and makes comparisons between suppliers more meaningful. Two suppliers reporting “99% purity” using different analytical approaches should not automatically be assumed to be reporting directly equivalent measurements.

10. Actual Numerical Results

Prefer certificates that provide measured data rather than only statements such as “Passed,” “Verified,” or “Research Grade.”

Depending on the test, actual results may include purity percentage, observed molecular mass, retention information, peak areas, and other measured characteristics.

The quality of the underlying information matters more than the visual appearance of the certificate.

11. Report or Accession Identifier

A report, accession, or other unique identifier strengthens traceability by providing a reference beyond the product and lot number.

For example, an IDUN-hosted 2026 certificate includes an accession identifier together with lot information, HPLC purity, LC-MS identity information, and testing date. This is particularly useful when maintaining records containing many certificates.

12. Signature, Review, or Issuing Information

Depending on the laboratory, a CoA may include analyst or reviewer information, laboratory identification, signatures, issue dates, or report numbers.

A missing signature alone does not prove a certificate is invalid. Evaluate issuing information together with product identity, batch, date, laboratory, methods, and actual results.

What a CoA Does Not Prove

A CoA is analytical documentation, not a universal safety certificate . It does not automatically establish:

Human or veterinary safety

Therapeutic efficacy

Regulatory approval

Sterility

Endotoxin status

Biological activity

Long-term stability

Suitability for a particular experiment

IDUN labels its catalog for research use and not for human consumption, so analytical documentation should not be interpreted as evidence of human-use safety or efficacy.

A 60-Second CoA Review

When time is limited, check these first:

Product identity — Is the material clearly identified?

Batch/lot — Does it match the material?

Test date — Is the analysis dated?

Testing laboratory — Is the analytical source identified?

HPLC result — Is an actual result reported?

Chromatogram — Is supporting data provided?

Mass spectrometry — Is identity addressed separately?

Actual results — Is there data rather than only “pass”?

Report/accession number — Is there an additional traceability identifier?

How IDUN’s Current CoA Library Fits

IDUN’s CoA library is organized around many fields researchers may want to review, including peptide, batch/lot, testing method, laboratory, purity, and test date. The archive also provides sorting, comparison, and download functions.

This makes it useful as a batch-documentation research tool , allowing researchers to examine certificates individually or compare documentation across products and production batches.

What Makes a CoA Weak?

Watch for these warning signs:

Generic certificate: Not linked to a particular lot.

Purity number only: No chromatogram or analytical context.

No testing method: The basis of the result is unclear.

No testing laboratory: Reduced traceability.

No test date: Timing of analysis is unknown.

No identity information: Purity and identity remain separate questions.

Product mismatch: The certificate describes a different compound.

Lot mismatch: The certificate may not describe the material being evaluated.

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