Why Peptide Tests Must Be Complementary

A matching mass result supports—but does not by itself prove—identity. Isomers, sequence variants, modifications, and mixed material can require additional structural evidence.

HPLC or UPLC separates and detects components under defined conditions. The resulting area percentage is method-dependent and is not the same as assay or net peptide content.

Endotoxin is not answered by mass spectrometry or a purity chromatogram. The assay must be shown suitable for the specific product matrix, including interference controls and appropriate reporting units.