Complexometric determination of mercury(II) by use of 4-amino-5-mercapto-3-propyl-1,2,4-triazole as replacing reagent

Abstract

A simple, rapid, and selective complexometric method is proposed for the determination of mercury(II). Mercury(II) is first complexed with excess of EDTA and the surplus EDTA is back-titrated (pH 5–6) with zinc sulphate solution, with Xylenol Orange as indicator. 4-Amino-5-mercapto-3-propyl-1,2,4-triazole is then added to displace EDTA from the Hg—EDTA complex and the released EDTA is titrated with zinc sulphate solution. Reproducible and accurate results are obtained in the range 1–40 mg of mercury, with a relative error of approximately 0.4%.