Chelatometric Determination of Pharmaceuticals. III: Determination of Phenylmercuric Acetate

A new method for the determination of phenylmercuric acetate by chelate titration is described. Addition of an excess of ethylenediaminetetraacetate (EDTA) to the aqueous solution of phenylmercuric acetate produces a precipitate of tetrakis (phenylmercuric) (ethylene-dinitrilo) tetraacetate and boiling this mixture at pH 3.5-5.0 produces Hg (II)-EDTA quantitatively. Excess of EDTA is back-titrated with the standard solution of Mg2+ or Zn2+. The reaction proceeds easily in the case of 1-300mg. of phenylmercuric acetate, and the determination is both accurate and precise. Application of this method to contraceptive tablets was discussed.