The separation of aqueous mixtures of glucose and fructose at high concentration up to 500 g/l has been investigated by using a semicontinuous chromatographic refiner (SCCR) with the calcium form DOWEX 50W-X12 ion exchange resin as adsorbent and water as the isocratic eluent. At high concentration the equilibrium isotherms could be approximately represented in terms of a quadratic expression which allowed for nonlinearity and coupling between the glucose and fructose equilibria. A plug flow model with mass transfer effect was presented for calculating both products and on-concentrations in the SCCR unit. Factors such as feed concentration, purge rate and total number of columns were explored and the validity of the model was experimentally confirmed.