Quality
How to read a certificate of analysis
6 min read · 21/08/2026
Purity percentages, HPLC traces and mass spec confirmation — what each section of a COA actually tells you.
Every vial we dispatch is tied to a batch, and every batch is tied to a certificate of analysis. But a COA is only useful if you can read it.
## HPLC purity High performance liquid chromatography separates the peptide from process-related impurities. The percentage quoted is the area of the main peak relative to total peak area.
## Mass spectrometry MS confirms identity: the observed molecular weight should match the theoretical weight of the target sequence within a tight tolerance.
## Batch and date A COA without a batch number and test date is not traceable. Ours carry both.
References
- Analytical methods for peptide characterisation, J. Chromatogr. A
This article is educational and summarises published research. It is not medical advice and does not describe human use. All Pepmol products are supplied for laboratory research only.