HPLC purity

High-Performance Liquid Chromatography (HPLC) separates the components of a mixture by passing them through a column packed with a stationary phase. UV detection at 220 nm captures peptide bonds; the area under the resulting chromatographic peak relative to the total signal is reported as percent area purity.

A peptide reported at "≥98% by HPLC" means that the main peak represents at least 98% of the total integrated UV absorbance. Common impurities are truncated sequences, deletion peptides, and oxidation products.