Complexometric determination of zinc(II) using 2,2 '-bipyridyl as selective masking agent

An indirect complexometric method is described for the determination of zin c(II) using 2,2'-bipyridyl as masking agent. Zinc(II) in a given sample sol ution is initially complexed with an excess of EDTA and surplus EDTA is tit rated with lead nitrate solution at pH 5.0-6.0 (hexamine), using xylenol or ange as indicator. An excess of 2,2'-bipyridyl is then added, the mixture s haken well and the EDTA released from the Zn-EDTA complex is titrated with standard lead nitrate solution. Results are obtained for 3-39 mg of Zn with relative errors less than or equal to 0.5% and standard deviations +/- 0.0 6 mg. The interference of various ions are studied. The method is applied f or the determination of zinc in its alloys and ores.