HPLC Testing

The primary analytical method used to determine peptide purity. A dissolved sample is injected into a column packed with stationary-phase material and eluted with a gradient mobile phase. Components separate by differential affinity for the stationary phase. UV detection at 214–220 nm produces a chromatogram where each impurity or degradation product appears as a separate peak. Purity is calculated as the ratio of the target peptide peak area to the total chromatogram area. Research-grade peptides should show ≥98% purity by HPLC.