HPLC purity testing for peptide reagents

High-Performance Liquid Chromatography (HPLC) is the gold standard analytical technique for quantifying peptide purity. Every peptide reagent sold by Peptiko is verified to ≥99% purity by HPLC-MS analysis.

How HPLC Works

HPLC separates molecules in a liquid sample based on their interaction with a solid stationary phase and a mobile solvent phase. For peptides, reversed-phase HPLC (RP-HPLC) is the most common method, exploiting differences in hydrophobicity between the target peptide and any impurities. Each component elutes from the column at a characteristic retention time, producing a chromatogram with distinct peaks.

Interpreting the Chromatogram

A high-purity peptide produces a single, sharp dominant peak at its expected retention time, with minimal additional peaks indicating impurities. The peak area is calculated as a percentage of total chromatogram area — this percentage represents the peptide purity. A ≥99% result means the target peptide accounts for at least 99% of all detected material.

HPLC-MS Confirmation

HPLC combined with mass spectrometry (HPLC-MS) provides not just purity quantification but also molecular identity confirmation. The mass spectrometer verifies that the detected molecule has the correct molecular weight for the target peptide, ruling out isobaric impurities that might otherwise go undetected.