What Is a Certificate of Analysis (COA)? How to Read One
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Quick answer
A certificate of analysis (COA) is a document that reports the laboratory test results for one specific production lot of a compound. For research peptides it typically lists the lot number, the identity result (mass spectrometry), the purity result (HPLC), the test methods used, the testing date, and the laboratory that performed the analysis. A COA applies only to the lot number printed on it.
The sections of a typical peptide COA
Most COAs follow the same structure, even when the layout differs between laboratories.
- Product name, sequence or molecular formula, and molecular weight
- Lot or batch number — the link between the document and your vial
- Appearance (for example, white lyophilized powder)
- Identity by mass spectrometry, with observed versus expected mass
- Purity by HPLC, usually with the chromatogram attached
- Additional assays when performed, such as endotoxin or water content
- Testing laboratory, test date, and an authorizing signature
Matching a COA to your vial
Always compare the lot number on the vial label with the lot number on the certificate. Results from one lot say nothing about a different lot, even of the same product.
If a chromatogram or mass spectrum is attached, the reported numbers should be consistent with it — for example, a single dominant HPLC peak for a high-purity result.
Why independent testing matters
Testing performed by an independent third-party laboratory, rather than only by the manufacturer, adds a layer of verification. Many research labs keep COAs on file alongside their own records for each lot they use.
Frequently asked questions
Does a COA apply to every vial of a product?
No. A COA applies only to the production lot whose number is printed on it. Check that the lot number on your vial matches the certificate.
What should a peptide COA include at minimum?
At minimum: the product name, lot number, identity result by mass spectrometry, purity result by HPLC, the test methods, the testing date, and the laboratory that performed the analysis.
How do I get the COA for an Atlas product?
Certificates of analysis are available for Atlas product lots. Email info@atlasresearch.cc with the product name and the lot number from your vial label.
For laboratory research use only. Not for human or veterinary use. This guide is educational and is not instructions for use.