Two analyses together characterise a peptide: reversed-phase HPLC answers how pure the material is, and mass spectrometry answers whether it is the right molecule.
RP-HPLC (purity)
Reversed-phase high-performance liquid chromatography separates components by hydrophobicity as they pass through a column, detected by UV absorbance. Purity is reported as the area of the main peak as a percentage of the total peak area — so a higher percentage means fewer co-eluting impurities.
ESI-MS (identity)
Electrospray-ionisation mass spectrometry measures the molecular mass of the material. Matching the measured mass to the expected mass confirms identity — that the peak HPLC quantified is actually the intended peptide.
Reading the numbers
A purity percentage is method-dependent and describes the tested lot, not the product line. Read it alongside the identity result on the same Certificate of Analysis.
For laboratory research use only. Not for human or veterinary use, and not intended to diagnose, treat, cure, or prevent any disease.