Peptide HPLC Purity Testing Explained
Purity figures appear on every research peptide listing, but the number only means something once you know the method behind it. This page describes the two analytical methods Amino Fuel Labs documents and what each one can and cannot establish.
Reversed-phase HPLC
High-performance liquid chromatography separates the target peptide from process-related impurities such as truncated sequences, deletion products and residual reagents. The detector output is integrated, and the target peak is expressed as a percentage of total peak area. That percentage belongs to the lot that was injected, which is why purity is reported per lot rather than per product.
Mass spectrometry for identity
Chromatographic purity says nothing about which molecule the main peak represents. Mass spectrometry supplies that missing half by measuring molecular mass and comparing it against the expected mass of the declared sequence. Purity plus identity together are what make a certificate useful; either one alone leaves an open question.
How to read a reported percentage
A figure such as 99% describes peak area under a specific method and gradient. Different laboratories can produce slightly different values for the same material, so compare figures only when the stated method is comparable. Treat any percentage without a named method, detection wavelength or analysis date as undocumented.
What HPLC does not measure
It does not measure sterility, endotoxin content, water content or biological activity; those are reported separately on the lot Certificate of Analysis where tested. It does not describe how material was handled after it left the laboratory. Amino Fuel Labs publishes no cGMP or cleanroom claim.
Related research peptides
Lab reports & documentation
Frequently asked questions
Is HPLC purity the same as identity?
No. HPLC quantifies peak area; mass spectrometry confirms the molecule matches the declared sequence.
Why does purity vary between lots?
Purity is measured on the material actually synthesised and injected, so each lot carries its own result.
Do you publish chromatograms?
Lot-matched certificates reporting HPLC purity and mass-spectrometry identity are available in the COA library.
Is the tested material for human use?
No. All compounds are supplied for laboratory research only.