Method for the fractionation of dextran by centrifugal precipitation chromatography

Recent advances in biotechnology and biochemistry have been facilitated by efficient separation methods for biopolymers, such as proteins and nucleic acids. On the other hand, research on polysaccharides is hindered by problems in their fractionation. For many decades, polysaccharides have been fractionated by stepwise ethanol precipitation, and even at the present time, almost all of their purification protocols include at least one such step, although it is tedious and inefficient. This paper describes a novel approach for chromatographic fractionation of polysaccharides by ethanol gradient precipitation using an open column under a centrifugal force field. Using a unique column design, chromatographic separation of polymers is achieved by subjecting the sample to a repetitive process of precipitation and dissolution along a long, spiral channel. In this article, we fully describe the principle, design of the prototype, and basic studies on various parameters for optimization of chromatographic conditions, using dextran as an example.