Selective complexometric determination of copper in ores and alloys using 2,2 '-bipyridyl as masking agent

An EDTA titration method is described for the determination of copper(II) i n the presence of other ions based on the selective masking ability of 2,2' -bipyridyl. Copper and other ions in a given sample solution are initially complexed with an excess of EDTA and the surplus EDTA is titrated with lead nitrate solution at pH 5.0-6.0 (hexamine), using xylenol orange as an indi cator. A known excess of 2,2'-bipyridyl solution (1% in 50% alcohol) is the n added, the mixture is shaken well and the released EDTA from the Cu-EDTA complex is titrated against standard lead nitrate solution. The interferenc e of various ions are studied and the method is applied to the determinatio n of copper in its ores and alloys. Reproducible and accurate results are o btained for 2.54-25.40 mg of copper with S.D. values < 0.04 mg. (C) 2000 El sevier Science B.V. All rights reserved.