Peptide purity is tested primarily by HPLC, which measures the target peptide as a percentage of the sample, and mass spectrometry, which confirms identity by molecular weight. HPLC answers how pure; mass spec answers is it the right molecule.
HPLC: measuring purity
High-performance liquid chromatography pushes the sample through a column that separates it into its components. The target peptide appears as the main peak, and its share of the total is reported as the purity percentage. A single tall, dominant peak indicates high purity.
Mass spectrometry: confirming identity
Mass spectrometry measures the molecular weight of the peptide. Because each sequence has a known expected weight, a match confirms the material is the correct molecule, not a similar impurity.
Browse research-grade peptides
Every Axis compound is third-party tested to 99.4%+ purity, with a certificate of analysis on every batch.
Why both are needed
Purity without identity is not enough, and vice versa. A peptide could be highly pure but the wrong molecule, or the right molecule but impure. Running both tests and reporting them on a certificate of analysis is what confirms a peptide is both pure and correct.
Key takeaways
- HPLC separates the sample and reports purity as an area percentage.
- A single dominant HPLC peak indicates high purity.
- Mass spectrometry confirms identity by molecular weight.
- Together they verify both purity and identity on the COA.
A note on research use
The peptides supplied by Axis Peptide Labs are reference compounds for laboratory and research use only. They are intended for qualified researchers working in academic, institutional, and analytical settings. They are not drugs, foods, cosmetics, or medical products, and they are not intended for human or veterinary consumption. Documented identity and documented purity are what matter most when sourcing a compound, both of which are published on the Axis certificates of analysis page.
