Step 1 — HPLC for Purity
High-Performance Liquid Chromatography separates the components of a peptide sample. The principal peak corresponds to the target compound; smaller peaks represent impurities or related sequences. The relative peak area gives a percentage purity figure — for example, ≥99%.
Step 2 — Mass Spectrometry for Identity
Mass spectrometry measures the mass-to-charge ratio of ions produced from the sample. By comparing the observed mass to the theoretical mass of the intended peptide sequence, the analyst confirms identity at the molecular level.
Step 3 — Documentation
Test results are summarized on a Certificate of Analysis (COA), which includes lot number, assay date, HPLC purity, identity confirmation, and recommended storage. The COA travels with each shipment so the receiving laboratory has a verifiable record for its notebooks.
Independent vs In-House Testing
Some suppliers test in-house only; others send representative samples to a third-party laboratory. Third-party testing provides independent confirmation of purity claims. We use independent HPLC verification for the compounds in our catalog — see our quality page for details.
This article is educational reference content. All products discussed are sold strictly for in-vitro laboratory research. Not for human consumption. Not approved by the FDA. Not intended to diagnose, treat, cure, or prevent any disease.