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A selective complexometric method of determination of manganese(II) using L-Cystine as masking agent

Author Affiliations

  • 1Department of Chemistry, St. Aloysius College, Mangalore-575003, Karnataka, India
  • 2Department of Chemistry, Srinivas Institute of Technology, Valachil, Mangalore-574143, Karnataka, India
  • 3Department of Chemistry, St. Aloysius College, Mangalore-575003, Karnataka, India

Res.J.chem.sci., Volume 9, Issue (4), Pages 30-33, October,18 (2019)


The determination of manganese(II) in the existence of various other different metal ions, a transparent speedy and accurate complexometric method is explained, depending on the selective masking ability of L-Cystine against Mn(II). Along with other associated metal ions, Mn(II) present in a given sample solution is first complexed with the surplus of EDTA and the leftover EDTA is then titrated against Zinc sulphate solution in the presence of Xylenol Orange as an indicator at pH5.0-6.0.A known excess of 1% L-Cystine solution is then supplemented to discharge the EDTA from Mn(II)-EDTA complex and mixed well. The displaced EDTA is again titrated with Zinc sulphate solution. The method goes well in the range 2.19-15.39mg of manganese(II) with the relative error ±0.5 and standard deviation & ≤0.03mg The issue of the existence of various other metal ions on the exactitude of the results has been studied. And the method can be used for the determination of Manganese in alloys.


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