A Highly Selective Complexometric Determination of Mercury (II) Using L-Tyrosine as a Masking Agent

Determination of mercury in the existence of various other metal ions, a transparent speedy and accurate complexometric method is described, depending on the selective masking ability of L-Tyrosine towards Hg (II). Along with other associated metal ions, Hg (II) present in a given sample solution is first complexed with an surplus of EDTA and the leftover EDTA is titrated with Zinc sulfate solution in the presence of xylenol orange as an indicator at pH 5.0- 6.0.A known excess of 0.02M L-Tyrosine solution is then added to discharge the EDTA from Hg (II)-EDTA complex and then it is mixed well. The displaced EDTA is again titrated with a Zinc sulfate solution. The method goes well in the range 4-80 mg of mercury (II) with the relative error ±0.4 and standard deviation ≤0.05 mg. The issue of the existence of various metal ions on the exactitude of the results has been studied. And the method can be applied for the determination of Mercury in alloys, in its synthetic mixtures of ions and its complexes.