Reading a Certificate of Analysis: A Quick Guide for Researchers
A Certificate of Analysis (CoA) is the document that tells you what a peptide batch actually contains, based on independent laboratory testing — rather than just what the label says. If you are sourcing research peptides, knowing how to read one properly is one of the most useful skills you can have.
What a CoA Should Include
- Identity confirmation — usually via Mass Spectrometry (MS), confirming the molecule matches the expected sequence.
- Purity percentage — typically from HPLC (High-Performance Liquid Chromatography), showing how much of the sample is the target peptide versus synthesis by-products.
- Batch or lot number — this should match the number printed on the vial you received.
- Testing laboratory — ideally an independent third party, not the manufacturer itself.
Why the Batch Number Matters
Purity can vary between production runs, even for the same product. A CoA is only meaningful if it corresponds to the exact batch you are holding — always check the batch number on your vial against the one on the certificate before relying on the results.
Our Approach
We make a Certificate of Analysis available for the batches we stock. If you cannot find the one you need on a product page, contact us with your order details and we will provide it directly.
This article is provided for general research information only. All products are sold strictly for laboratory research use.