Rapid absorptiometric determination of beryllium with aluminon

Abstract

Beryllium forms a red complex with aluminon in a faintly acidic solution, the absorption maximum of the complex lying at near 540 m mu . It is found that the reaction itself and also the masking of intefering ions with EDTA had better be accelerated by heating of the solution and that the sensitivity becomes greater in sodium acetate buffer than in ammonium acetate buffer, the optimum pH for the reaction being dependent on concentration of aluminon or on presence of gelatin. Absorbancy increases with increasing concentration of aluminon and in presence of gelatin but decreases with increasing concentrations of EDTA and ammorium or alkali-metal ions. The effect of alkali-metal ions on the absorbancy decreases with increasing concentration of aluminon, although the effect of pH becomes greater. To a solution containing 4 to 32 gamma of berylliuin are added 1 ml (or 5 ml) of 2.5% EDTA, 10 m1 of reagent solution (0.500 g of aluminon, 272 g of sodium acetate trihydrate, and 27 ml of acetic acid in 1 liter, pH 5.3 plus or minus 0.05), and 5 ml of 0.5% gelatin. The solution is gently boiled for 5 min, cooled, and diluted to 50 ml with water, themore » optimum pH in this case being 5.1 to 5.5. Absorbancy is measured with Hitachi No. 53 filter (530 m mu ). The determination is carried out with an error of less than 2%, and the time re quired for an analysis is about 20 min. Aluminum less than 250-fold of beryllium and copper, iron, lead, zinc, calcium, or magnesium less than 2000-fold do not interfere. The method is easily applicable to various kinds of samples, i.e., beryllium ores, intermediates, or products from beryllium -- copper industries. (auth)« less