Polarographic Determination of Tin and Antimony in Iron and Steel

For the estimation by ploarography of small amounts of tin and antimony contained as impurities in iron and steel, it was necessary to remove the effect of interference of iron. These impurities were, therefore, separated from iron by co-precipitating with manganese dioxide. The precipitate was decomposed with hydrochloric acid and hydrogen peroxide, and tin was reduced with aluminium foil to Sn^ and its polarogram was taken in ammonium chloride solution. Antimony solution was heated with sulfuric acid till the evolution of white fume to reduce it to Sb^ and the polarogram was taken in 0.1N hydrochloric acid. 0.02～0.1 per cent of tin and 0.005～0.1 per cent antimony in iron and steel could be determined