Sorption and exclusion of polar solutes on cross-linked polymers

Summary The interstitial volume in ion-exchange columns packed with beads of gel-type is a well defined quantity. The retention volumes of dextran and high relative molecular mass polyethylene glycols are identical. For macroreticular resins and cross linked polyvinylpyrrolidone the retention volume depends on the structure and relative molecular mass of the polymer indicating that no strict borderline exists between the resin phase and the mobile phase.