Extraction of caffeine using aqueous two-phase systems containing ionic liquid and sorbitol

In this study, a new aqueous two-phase system consisting of tetrabutylphosphonium bromide ionic liquid and sorbitol was selected. The partitioning of caffeine as a substance having many applications in the food and pharmaceutical industries was evaluated in this system. The effect of the variables such as the weight percentages of the ionic liquid and carbohydrate on the partitioning of caffeine was shown. The results indicated that by increasing the ionic liquid weight fraction and the sorbitol weight fraction, the partition coefficient of caffeine increased. Nevertheless, in all stages, the caffeine had a tendency to migrate towards the ionic liquid-rich phase. Also, the results indicated that the temperature had not an effect on the partitioning of caffeine. The recovery percentage of caffeine was reported in this system. The experimental results of the partition coefficient of caffeine were fitted by different regression models, and the most efficient regression model was selected based on the statistical analysis.