Isometric Certificate of Analysis document with grouped placeholder rows, a seal, and a magnifier examining a line
Mindful Research

Reading a Certificate of Analysis (COA) Line by Line

Updated By: Mindful Research Team2 min read

Key takeaways

  • A COA documents a batch's identity, purity, and the methods used to measure them.
  • Identity comes from sequence, formula, CAS, and a measured molecular weight matching the theoretical value.
  • Purity should be reported as a percentage with its method named (usually HPLC).
  • Mass spectrometry's observed mass should match the expected mass.
  • A batch-specific, dated COA is stronger than a generic spec sheet.

A Certificate of Analysis (COA) documents a peptide batch's identity, purity, and the methods used to measure them. This guide walks through each line so you can read one with confidence.

Identity fields

The product name, sequence, molecular formula, and CAS number (where applicable) identify the compound. The measured molecular weight should match the theoretical value for that sequence.

Purity and the method

Purity is reported as a percentage and should name the method, typically HPLC, along with the conditions. A COA that reports purity without a method is weaker evidence.

Mass spectrometry result

The COA usually lists the observed mass from mass spectrometry next to the expected mass. A close match confirms the material is the intended molecule.

Appearance, solubility, and other tests

Physical description (for example, a white lyophilized powder), solubility notes, and any endotoxin or water-content results round out the picture.

Batch-specific vs. generic

The strongest COA is batch-specific, tied to the lot you received, with dated test data. A generic specification sheet describes what a product should be, not what your specific batch measured.

Find a COA: search every third-party lab report by product or batch number in our certificate of analysis library.

Related research guides

Research-use note

All materials discussed are supplied for in vitro laboratory research use only.

Frequently asked questions

What is a Certificate of Analysis?

A document that records a specific peptide batch's identity, purity, and the test methods and results used to verify them.

How do I confirm identity on a COA?

Check that the measured molecular weight matches the theoretical value for the stated sequence, supported by the mass-spectrometry result.

What makes a COA trustworthy?

Batch-specific, dated data with named methods (HPLC for purity, mass spectrometry for identity), rather than a generic specification.

What is the difference between a COA and a spec sheet?

A COA reports what your batch measured; a spec sheet describes what the product should be in general.

Research use only?

Yes, in vitro laboratory research use only.

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