Selective method for the complexometric determination of copper in alloys and ores

Abstract

A complexometric method for the determination of copper(II) in the presence of other metal ions is described. The method is based on the selective complexing ability of mercaptosuccinic acid towards Cu(II). Copper, present in a given sample solution, is initially complexed by the addition of EDTA solution and the excess is titrated against zinc solution. A known excess of mercaptosuccinic acid is then added to release EDTA from the Cu(II)-EDTA complex, which is subsequently titrated against zinc solution. The amount of EDTA replaced from the complex is equivalent to the amount of Cu(II) in the solution. Various metal ions such as Pb(II), Ni(II), Co(II), Cd(II), Fe(III), Al(III), Ti(IV), Th(IV) and rare earths and anions such as Cl^–, NO₃^– SO₄^2–, acetate, tartrate and F^– were found not to interfere. Interference from ions such as Sn(IV), Zr(IV), Bi(III), Hg(II) and Pd(II) can be overcome by the use of suitable masking agents. The method has been successfully applied to the analysis of various alloys and ores.