Selective complexometric determination of nickel(II) in isolation complexes and alloys using 2,2 '-bipyridyl as a releasing agent

A rapid selective complexometric method is described for the determination of nickel(II) in the presence of various cations and anions using 2,2'-bipy ridyl as the masking agent. Nickel(II) in an aliquot is initially complexed with an excess of EDTA and the excess EDTA is titrated with lead nitrate a t pH 5.0-6.0 (hexamine or acetate buffer) using xylenol orange as indicator . An excess of 5% 2,2'-bipyridyl solution is then added. The mixture is sha ken well and the EDTA released from the Ni(II)-EDTA complex is titrated wit h standard lead nitrate solution. Results are obtained for 1.2-58.7 mg of n ickel(II) with relative errors <0.3% and standard deviations < 0.04 mg. The interference of various cations and anions are studied. The method is exte nded for the quantitative determination of nickel in its alloys and complex es.