Coprecipitating ammonium–iron(iii)–hexacyanoferrate(ii) from aqueous dispersion with albumin and trichloroacetic acid

Abstract

Ammonium–iron(III)–hexacyanoferrate( II) (AFCF) is a caesium-binding agent used, for example, to prevent the absorption of radioactive caesium from the alimentary tract of domestic animals. Owing to its colloidal nature, its separation from aqueous solution with standard methods is tedious, complicating in vitro studies. A new and simple method for separating AFCF from water and water-soluble components was developed, based on quantitative coprecipitation with bovine albumin and trichloroacetic acid (TCA). The resulting precipitate and supernatant can be separated with low centrifugal forces. Bound caesium follows AFCF into the precipitate, whereas free caesium remains in solution. This makes the method a potential tool in the study of the thermodynamic and kinetic properties of AFCF–caesium interactions in vitro. Effects of different factors, such as concentrations of components, speed and duration of centrifugation and temperature, are described.