scope:

The method describes the determination of zinc in phosphor-bronze by two polarographic methods, tin and copper having previously been removed.

Method A uses D.C. polarography in an ammonia-ammonium chloride base solution and Method B uses A.G. polarography in a potassium thiocyanate base solution.

Both methods are applicable to bronzes containing up to 0.1 per cent of zinc and higher amounts up to about 0.5 per cent can be determined by ta1cing suitable aliquots. For material containing more than 0.1 per cent of iron Method A must be used but when apparatus is available for using A.C. polarography Method B is preferable for lower quantities of iron.