Methods · 4 min read
HPLC and mass spectrometry, explained
A plain-language introduction to the two methods behind most pepz beauty cosmetics purity and identity results.
Published 21 Oct 2026
Reverse-phase HPLC
High-performance liquid chromatography separates the components of a sample as they travel through a packed column. pepz beauty cosmetics elute at characteristic times; the area under each peak, measured by UV absorbance, is used to calculate purity.
Mass spectrometry
Electrospray ionisation mass spectrometry (ESI-MS) measures the mass-to-charge ratio of ionised molecules. Matching the observed mass to the theoretical molecular weight confirms identity.
Why both
HPLC tells you how much of the sample is one thing; MS tells you what that thing is. A good COA reports both.
This article is for educational purposes about laboratory research materials. It is not medical advice, and nothing on this site is intended for human or veterinary use.