Alkalimetric determination of mercury by use of its reaction with 1-mercaptopropan-2,3-diol.

The reaction of mercury(II) with 1-mercaptopropan-2,3-diol to form its mercaptide and protons, and alkalimetric titration of the acid produced is proposed as a simple and rapid method for determination of mercury. Any acid already present is first neutralized to Phenol Red indicator after complexation of the mercury(II) with iodide to avoid precipitation of mercuric oxide. Mercury metal, its insoluble salts in both oxidation states, complexes and organomercury compounds have been determined after digestion with nitric acid and persulphate to produce mercury(II). The interference of copper(II) is avoided by its reduction and solvent extraction with 2-benzoxazolethiol. The method is unaffected by the presence of large amounts of halides, oxalate, tartrate, citrate, fluoride, EDTA, thiocyanate and thiourea, which all interefere severely in complexation titrations.