Simultaneous Estimation of the Binding Constant of Saccharide to Sodium Ion and the Swelling Pressure of Cation-exchange Resin

The apparent distribution coefficients, Kapp, of some mono-, di- and trisaccharides onto cation-exchange resins in the sodium-ion form and having the divinylbenzene (DVB) contents of 4, 6 and 8% were measured at 25°C. A method for simultaneously estimating the swelling pressures of the resins and the binding constants, B, of the saccharides to the sodium ion was proposed. By applying the method to the Kapp values of mono- and disaccharides, the swelling pressures of the resins having the DVB contents of 4, 6 and 8% were estimated to be 18.9, 30.8 and 37.8 MPa, respectively, and the B values of the mono- and disaccharides were also estimated simultaneously. The B values of the trisaccharides were calculated using the estimated swelling pressures. The B values ranged from 0.24 to 2.2 L/mol. The tri-, di- and monosaccharides had higher B values in this order. There was a tendency that the solute, which can form a tridentate complex with the sodium ion, contains high numbers of axial-equatorial and equatorial-equatorial complexing hydroxyl groups.