How to read a peptide certificate of analysis (COA)
How to read a peptide certificate of analysis (COA)
Last updated: 2026-10-10 · Research use only. Not for human or veterinary use.
Short answer
A certificate of analysis (COA) is a lot-specific document that lists the tests performed on a batch, the acceptance criteria and the results. For a synthetic peptide it typically covers appearance, identity by mass spectrometry, purity by HPLC and sometimes net peptide content, water, counter-ion and endotoxin. [1]
At a glance
| Term | Definition / specification |
|---|---|
| Lot / batch number | Links the document to a specific vial run |
| Identity | MS observed mass vs theoretical |
| Purity | RP-HPLC area %, with chromatogram |
| Content (optional) | Net peptide content by AAA or nitrogen |
| Other (optional) | Water, counter-ion, endotoxin, appearance |
| Date and sign-off | Test date and responsible analyst or QA |
Check the lot
A COA applies to one lot. Confirm the lot number matches the vial before relying on the figures.
Look for raw data
A chromatogram and a mass spectrum let a reader check that the stated numbers follow from the data. Impurity profiling methods such as LC-MS are what generate these records.
FAQ
Is a COA the same for every lot?
No. Each lot is tested and documented separately.
Does Sable publish COAs on product pages?
There is a CoA for every lot — request yours at /coa-request and we email it within 2 hours. See /education/what-a-documentation-request-is.
Related reference pages
- What HPLC purity means for a research peptide
- Mass-spectrometry confirmation of peptide identity
- Net peptide content vs gross weight
- Reference index
Sources
- De Spiegeleer B et al. Impurity profiling quality control testing of synthetic peptides using liquid chromatography-photodiode array-fluorescence and liquid chromatography-electrospray ionization-mass spectrometry: the obestatin case. Anal Biochem. 2008. PMID: 18342612
- Verbeke F et al. Quality evaluation of synthetic quorum sensing peptides used in R&D. J Pharm Anal. 2015. PMID: 29403929 · PMC5762210
- Choules MP et al. Quality Control of Therapeutic Peptides by (1)H NMR HiFSA Sequencing. J Org Chem. 2019. PMID: 30793905 · PMC6452441
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Research use only. This page describes laboratory chemistry and analytical methods. It is not advice on any use in people or animals.
CoA for every lot — request yours and we email it within 2 hours.
Research use only. Not for human or veterinary use.