What is reversed-phase HPLC?
Reversed-phase HPLC (RP-HPLC) is the dominant high-performance liquid chromatography mode for peptide purity verification. The stationary phase is a non-polar (C18 or C8) bonded silica; the mobile phase is a polar water-organic solvent gradient. Peptides elute at retention times set by their hydrophobicity, with target peptide separated cleanly from sequence variants and process-related impurities.
What the research literature says
RP-HPLC inverts the traditional “normal-phase” chromatography polarity convention — instead of a polar stationary phase plus non-polar mobile phase, RP-HPLC uses a non-polar bonded-silica stationary phase plus polar water-organic gradient. The C18 (octadecyl-bonded silica) column is the standard pick for peptide analysis because it provides broad-spectrum retention for the hydrophobic-amino-acid-content range typical of research peptides.
The mobile-phase gradient typically runs from water (with 0.1% trifluoroacetic acid as ion-pairing modifier) to acetonitrile (also with 0.1% TFA). The gradient elutes peptides in order of increasing hydrophobicity — peptides with high arginine/lysine content elute early; peptides with high phenylalanine/tryptophan/leucine content elute later. The chromatogram is detected at 214 nm (peptide-bond absorbance) for purity quantitation.
The analytical-validation framework for RP-HPLC peptide methods is set out in ICH Q2(R1) and the USP <621> general chapter on chromatography. The USP <1086> general chapter on impurities covers the impurity-identification and reporting-threshold framework.
Why this matters in research context
RP-HPLC matters in peptide-research contexts as the dominant analytical method for purity verification on every credible peptide certificate of analysis. Researchers reviewing a peptide COA should understand that the headline purity percentage is the RP-HPLC peak-area ratio at 214 nm — the same number derived from different methods (e.g., capillary electrophoresis, size-exclusion chromatography) may not be directly comparable.
Related compounds
- HPLC purity verification (glossary entry) — broader analytical methodology
- Lab results page — per-batch COA access
Related research questions
References
- ICH Q2(R1) — Validation of Analytical Procedures: Text and Methodology. International Council for Harmonisation.
- USP <621> Chromatography. General chapter defining system-suitability and reporting for chromatographic methods. United States Pharmacopeia.
- USP <1086> Impurities in Drug Substances and Drug Products. United States Pharmacopeia.
Research-questions pages describe research-context use of peptide-research terminology. They do not constitute medical, veterinary, or clinical advice. Every compound in the Ronin catalog is sold strictly for laboratory and research use only.