A novel type of coil planet centrifuge is introduced. The apparatus holds a coil holder in such a way that the axis of the holder is positioned perpendicular to and at a fixed distance away from the centrifuge axis. In maintaining the above orientation the holder undergoes synchronous planetary motion, i.e., revolution around the central axis of the centrifuge and rotation about its own axis at the same angular velocity. Mathematical analysis of acceleration generated by this planetary motion revealed a unique distribution pattern of centrifugal force vectors which promises a high performance of the present system in countercurrent chromatography. Potential capability of the apparatus has been examined with three types of coiled columns all coaxially mounted around the holder. In single-layer coils typical solvent systems display characteristic hydrodynamic distribution which ensures a stable retention of the stationary phase against heavy sample loading in preparative separations. Direct observation of the hydrodynamic motion in the rotating spiral column revealed vigorous mixing of the two solvent phases throughout the area which indicates a high partition efficiency of the present method. Gram-quantity preparative separations were performed in the multilayer coil with two different sets of test samples: Isocratic elution of dinitrophenyl amino acids yielded high partition efficiency of 1,600 theoretical plates while versatility of the method was demonstrated on gradient elution of dipeptides including two pairs of sequential isomers.
