Toroidal coil counter-current chromatography study of the mass transfer rate of proteins in aqueous-aqueous polymer phase system.

The cause of excessive band broadening of protein samples in polymer phase partitioning by counter-current chromatography (CCC) was investigated. A simple rotary device was constructed to measure the mass transfer rates of five samples including potassium dichromate, methylene blue, lysozyme, ovalbumin and human serum albumin. The results indicated that the mass transfer rates of these samples are closely correlated with their molecular masses: the higher the molecular mass, the lower the mass transfer rate. These findings are also consistent with the partition efficiencies of these samples in the same solvent system by CCC. The beneficial effect of the Coriolis force demonstrated in protein separations by the toroidal coil centrifuge may be reasonably explained on the basis of the mass transfer resistance of protein molecules through the interface: we speculate that when the Coriolis force acts parallel to the effective coil segment it can produce large interfacial areas by dispersing the mobile phase into the stationary phase, thus accelerating the mass transfer rate of protein samples.