Indirect Complexometric Determination of Mercury (II) Using Sodium Thiosulfate as a Masking Reagent

✍ Scribed by C.H.R. Nambiar; B. Narayana; B.Muralidhara Rao; Biju Mathew; B. Ramachandra

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 49 KB
• Volume: 53
• Category: Article
• ISSN: 0026-265X
• DOI: 10.1006/mchj.1996.0025

✦ Synopsis

A complexometric method for the determination of mercury in the presence of other metal ions based on the selective masking ability of thiosulfate toward mercury is described. Mercury (II) present in a given sample solution is first complexed with a known excess of EDTA and the surplus EDTA is titrated against zinc sulfate solution at pH 5.0-6.0 (hexamine) using xylenol orange/ methylthymol blue complexone as indicator. A known excess of sodium thiosulfate solution (1%) is then added, the mixture is shaken well, and the EDTA released from the Hg-EDTA complex is titrated against a standard zinc sulfate solution. Reproducible and accurate results are obtained for 2.5-78 mg of mercury with relative errors <0.4% and standard deviations Յ0.05 mg. The interference of various ions were studied. This method was applied to the determination of mercury (II) in its alloy compositions. Academic Press, Inc.