Effects of the Planetary Motion of a Coiled Column on Protein Separation by the Nonsynchronous Coil Planet Centrifuge

Abstract The effects of rotational speed and direction of revolution of the coiled separation column on protein separation were examined using a rotary‐seal‐free nonsynchronous coil planet centrifuge (CPC) fabricated in our laboratory. This apparatus has a unique feature that allows a freely adjustable rotational speed of the coiled separation column at a given revolution speed. The separation was performed using a set of stable proteins including cytochrome C, myoglobin, and lysozyme with an aqueous–aqueous polymer phase system composed of 12.5% (w/w) polyethylene glycol (PEG) 1000 and 12.5% (w/w) dibasic potassium phosphate. A series of experiments revealed that the head to tail elution mode produced better stationary phase retention and higher peak resolution regardless of the choice of the mobile phase. The best result was obtained in the head to tail elution mode by the clockwise (CW) coil rotation for the lower mobile phase or by the counterclockwise (CCW) coil rotation for the upper mobile phase, both under CCW revolution of the rotor.