Source of Aromatic Affinity to 'Sephadex' Dextran Gels

SHORTLY after the development of dextran gels as packing material for size separation of solutes by gel chromatography (gel filtration) 1 , the sorption properties for low molecular weight aromatic substances were observed 2 . In spite of numerous investigations, some of which compared molecular structure with degree of retardation, and some of which exploited the side effects of gel chromatography for actual separation problems 3 , no interpretation was given for these rather strong interactions. Aromatic and heterocyclic substances are sometimes retarded during liquid chromatography on various sorbents such as charcoal, cellulose, silica, alumina oxide and polyacrylamide 3 , but the effects are much less pronounced than in the case of ‘Sephadex’ dextran gels. The sorption properties of ‘Sephadex’ gels should be divided into two classes: ( a ) the “mass action” and ( b ) special “binding” forces between solutes with π-electrons and the ‘Sephadex’ matrix. It is the nature of this specific binding that we wish to describe.