Selective Partitioning of Alkaloids in Alcohol- Carbohydrate Aqueous Two- Phase Systems

The new aqueous two-phase systems (ATPS) composed of saccharides and propanol was produced in this work. The main elements that control the phase splitting aptitude of these systems were studied. Two alkaloids (caffeine and codeine) and a flavoring antioxidant (vanillin) were used as target biomolecules for evaluating the extraction performance of propanol-carbohydrate ATPS. Because of the difference in the electric charge of caffeine and codeine in the produced ATPS, and also due to the difference in the water content and hydrophilic nature of the coexisting phases, the propanol- carbohydrate ATPS showed a proper selectivity for separation of these alkaloids. The partitioning experiments revealed that caffeine and vanillin are present as neutral species and preferentially concentrate in the alcohol-rich phase, however, codeine is present mostly in the cationic form and has a preferable orientation for the carbohydrate-rich phase. In order to optimize the selectivity of propanol-carbohydrate ATPS to separate similar biomolecules, factors such as the chemical structure of saccharides, temperature, and tie-line length were addressed.