Plasticized liquid membranes (PLM) can be used to selectively remove sugars from the hydrolysate, thereby eliminating the problems associated with contaminants and producing a desirable sugar feedstock. PLMs are lipophilic in nature and are robust in a variety of aqueous environments. In this research, PLMs containing carrying agents such as quaternary ammonium salts and/or complexing agents such as aryl boronic acids are tested with model glucose/xylose solutions, the sugars most commonly found in biomass hydrolysate. Composition of the membranes was varied by changing concentrations of the carrying agents and plasticizing agents. The effects of the membrane porosity, thickness, and composition on sugar flux and membrane stability are reported.