Analysis of Acceleration Produced by Planetary Motion in a Nonsynchronous Coil Planet Centrifuge

Abstract

The nonsynchronous coil planet centrifuge has a unique mode of planetary motion such that it provides freely adjustable coil rotation under a given centrifugal force field, and it produces an acceleration which fluctuates in a plane perpendicular to the axis of the holder. The two modes of planetary motion may be expressed as P_forward (coil rotation and revolution in the same direction) (revolution/rotation=clockwise CW/CW or counterclockwise CCW/CCW) and P_backward (coil rotation and revolution in the opposite directions) (revolution/rotation=CW/CCW or CCW/CW). The present study describes the analysis of acceleration produced by planetary motion in this apparatus. Our analysis is based on the equation for the absolute value of acceleration (A) in a given point on the column holder. A is calculated from each value obtained at the maximum and the minimum. The result indicated that the maximum value of A in P_forward is larger than that in P_backward under the same rotational rate, while the minimum value of A in P_forward is smaller than that in P_backward. A higher rotational rate increases the difference of the value between P_forward and P_backward. The overall results may support that the difference of maximum A and minimum A (ΔA) between P_forward and P_backward affects the retention of the stationary phase. Differences were observed experimentally in a previous study on protein separation with an aqueous two‐phase solvent system using the nonsynchronous CCC apparatus.

Keywords:

• Countercurrent chromatography
• Nonsynchronous coil planet centrifuge
• Planetary motion
• Acceleration

Acknowledgments

This work was supported in part by grants from the Ministry of Education, Culture, Sports, Science, and Technology of Japan and also from College of Pharmacy, Nihon University, Chiba, Japan.