countercurrent chromatography and centrifugal partition chromatography are two different instrumental realization of the same liquid–liquid chromatographic theory. countercurrent chromatography usually uses a planetary gear motion without rotary seals, while centrifugal partition chromatography uses circular rotation with rotary seals for liquid connection. ccc has interchanging mixing and settling zones in the coil tube, so atomization, extraction and settling are time and zone separated. inside centrifugal partition chromatography, all three steps happen continuously in one time, inside the cells.