Mechanism of transport of sugars across a supported liquid membrane using methyl cholate as mobile carrier

A supported liquid membrane was prepared by impregnation of commercial microporous polymer film with methyl cholate in cyclohexane and was used to study transport of various sugars. The stability constant and apparent diffusion coefficient of carrier-sugar complex were determined. The absence of a percolation threshold excludes a fixed-site jumping mechanism and supports a solution–diffusion mechanism of carrier–sugar complex in the membrane. However, the existence of a relation of inverse proportionality between the stability constant and the apparent diffusion coefficient suggests a mobile-site jumping mechanism where the sugar is relayed along a sequence of mobile carriers. The notable difference between the values of the stability constant of the various sugars studied confirms their molecular recognition by the methyl cholate. The HOCH2 group is necessary for stable carrier–sugar complexes, this can be explained by the long distance between O-3 and O-12 of methyl cholate.