Disodium EDTA is used in an indirect method for the amperometric titration of tungsten in minerals.This is based on the precipitation of tungsten as lead tungstate.The precipitate is dissolved in 1 M sodium hydroxide and 1 M sodium tartrate.The latter serves also as a supporting electrolyte.Titrate lead ions with 0.05 M disodium EDTA at -0.70 to -0.80 volt in NH₃-NH₄Cl buffer solution.The amount of tungsten can then be found by calculation.The results found are comparable to those found with ammonium nitrate method.