CPC does not use silica or any other solid sorbents, while the stationary phase is always a liquid. The stationary phase is retained within the separation cell by a strong centrifugal force, and mobile phase is constantly pumped through the stationary phase. During the separation process, the compounds are distributed between the stationary and mobile phase in accordance with their partition coefficients. The compounds with lower partition coefficients are eluted first followed by the other compounds with higher partition coefficients.
Technically, the extraction takes place inside small chambers (called “cells”) connected in series, which can be corresponded to classical chromatography columns connected one after the other. To ensure the retention of the stationary phase, the cells are mounted on the constantly spinning rotor. The centrifugal force ensures the phase border between the liquids with different density and helps the stationary phase not to be mixed and/or pumped out with the mobile phase.
The solvents coming out of the CPC are continuously analyzed and a chromatogram is compiled in real-time for monitoring using a UV‑VIS detector. Other methods (refractive index, conductivity, light scattering, optical rotation) can be considered for detection. Based on the chromatogram, the output is fractionated into several collecting vessels.