Peptides 101: Understanding HPLC Purity, Lyophilization, and Mass Spectrometry

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Elena Rostova, MSc (Director of Analytical Quality)

MWpeps Molecular Biosciences Research Division

Ensuring rigorous purity in peptide synthesis is foundational for reproducible scientific results. When sourcing research compounds, understanding the analytical metrics on a Certificate of Analysis (COA) is vital.

### HPLC (High-Performance Liquid Chromatography)
HPLC purity measures the percentage of the target peptide peak relative to all UV-absorbing impurities. For demanding in vitro and in vivo assays, a purity threshold of ≥99.0% is standard to eliminate confounding bioactivity from truncated sequences or deletion peptides.

### Mass Spectrometry (LC-MS)
Liquid chromatography-mass spectrometry confirms the molecular weight of the synthesized compound. Discrepancies between theoretical and experimental mass indicate sequence errors or incomplete deprotection during solid-phase peptide synthesis (SPPS).