The invention relates to a process for the liquid-phase separation of glucose from a mixture of C5 and C6 sugars comprising at least xylose and glucose, by adsorption of glucose on a zeolitic adsorbent based on FAU-type zeolite crystals having an Si/Al atomic ratio strictly greater than 1.5 comprising barium, wherein: said mixture is brought into contact with said adsorbent, by liquid chromatography, to obtain a xylose-enriched liquid phase and a glucose-enriched adsorbed phase; on the one hand, said xylose-enriched liquid phase is recovered and said phase adsorbed on said adsorbent is desorbed by means of a desorption solvent in order to recover the glucose on the other hand.