Background: Motion of the two mutually immiscible liquids in hydrodynamic countercurrent
chromatographic systems is speculated based on the observation of their behavior in a
closed coiled tube rotating in unit gravity.
Materials and Methods: The experiment revealed an up and down pattern of four stages of twophase
volume ratio occupied at the head end of the coil according to the rotation speed. These
two-phase behaviors are comprehensively explained on the bases of interplay between the unit
gravity and centrifugal force generated by rotation of the coil. This theory is successfully extended
to explain the two-phase behavior in a coil undergoing the type-I and type-J planetary motions.
Results and Discussion: The type-I planetary motion produces the centrifugal force distribution
similar to that of slowly rotating coil in unit gravity (Stage I), where both phases competitively
move toward the head of the coil. In contrast, the type-J planetary motion displays complex distribution
patterns of centrifugal force according to the location of the coil on the holder hence the
two-phase motion varies with the ß values. When ß is 0.5 – 0.75, the force pattern simulates that
of the rotating coil in unit gravity at 120 rpm (Stage III) where the lighter phase moves toward the
head leaving the heavier phase behind.
Conclusion: This clearly demonstrates the importance of the proper choice of ß values in highspeed
countercurrent chromatography utilizing the type-J planetary motion.
Keywords: Archimedean screw effect, countercurrent chromatography, force distribution diagram, hydrodynamic CCC system,
type-I planetary motion, type-J planetary motion.
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