How to Verify Peptide Purity: HPLC & Mass Spec Guide
Peptide purity verification is fundamental to reliable research. Understanding HPLC (High-Performance Liquid Chromatography) and mass spectrometry results allows researchers to confirm they’re working with the correct compound at the stated purity level.
Why Purity Matters
Impure peptides can produce misleading research results, contain degradation products or synthesis byproducts, and lead to inconsistent dosing. Always verify purity through third-party certificates of analysis (COAs) before beginning research.
Understanding HPLC Results
HPLC separates peptide components by passing the sample through a column at high pressure. The result is a chromatogram showing peaks: the main peak represents the target peptide, and smaller peaks represent impurities. Purity is calculated as: (main peak area ÷ total peak area) × 100%. Research-grade peptides should show ?98% purity, with premium suppliers like Proxiva Labs achieving 99.99%.
Understanding Mass Spectrometry
Mass spec confirms molecular identity by measuring the mass-to-charge ratio of the peptide. The observed mass should match the theoretical molecular weight within acceptable tolerance (typically ±1 Da). This confirms you have the correct compound, not just a pure one.
Reading a Certificate of Analysis
A quality COA should include: HPLC purity percentage, mass spec molecular weight confirmation, appearance description, batch/lot number, date of analysis, and the testing laboratory name. Learn more about interpreting COAs in our COA reading guide.
Third-Party vs In-House Testing
Third-party testing by independent laboratories provides unbiased verification. In-house testing by the manufacturer may have conflicts of interest. The gold standard is third-party testing by an ISO-accredited laboratory.
Related Articles: What is Peptide Purity? | Third-Party Testing Guide | Peptide Quality Guide
For research use only. All Proxiva Labs peptides include third-party HPLC and mass spec COAs.