Fractionation of a polymer using a preparative-scale continuous chromatograph

Summary The construction and operation of a liquid preparativescale continuous chromatograph is described. The chromatographic bed is arranged in a series of interconnected vertical columns and is rotated whilst one end of the tube bundle is closed by a stationary plate through which liquids enter and leave the bed. The problem of maintaining an efficient seal is described. The chromatograph was commissioned by continuously fractionating dextran on porous silica beads with water as eluent. Results show that as the feed concentration was increased, the fractionation obtained deviated markedly from that expected from basic GPC theory, but that the relative molecular mass distribution of the feed was still narrowed with feed concentrations of 20% w/v.