Separation of microgram quantities of aluminum and iron(III)

The separation of microgram quantities of ferric iron and aluminum can be effected by passage of an acidic thiocyanate solution through the anion exchange resin Amberlite IRA-400A. The anionic complex of iron and thiocyanate remains on the column whereas aluminum passes through with the eluate. This method has been utilized in the separation of up to 200 μg of iron from comparable amounts of aluminum thus permitting the spectrophotometric determination of the latter in caustic liquors and other alkali products.