Speciation of aluminum in tea infusion by ion-exchange resins and flame AAS detection

Abstract

In this study, it was attempted to fractionate aluminum that bound to hydrolyzable polyphenols and its cationic species, and to determine their concentrations in tea infusion by using ion exchange resins and flame AAS detection. In order to separate the hydrolyzable polyphenols bound aluminum species Amberlite XAD-7 resin was used while Chelex-100 resin was used to separate cationic aluminum species. For separation of aluminum species, after the optimization study based on the model solutions, the effluent from column filled with Amberlite XAD-7 was pumped directly through the column filled with Chelex-100 resin. Aluminum in all effluents was determined by FAAS method. It was found that about 30% of aluminum from black tea leafs transfers into the infusion that contains 11-12 mg l(-1) of Al and that about 10-19% of total aluminum in tea infusion is present as cationic species, while about 28-33% of as hydrolyzable polyphenols bound aluminum.