SIMULTANEOUS DETERMINATION OF ZINC AND NICKEL WITH 2-(2-PYRIDYLMETHYLENEAMINO)PHENOL BY FIRST-DERIVATIVE SPECTROPHOTOMETRY

A first-derivative spectrophotometric method using a zero-crossing technique of measurement is described for the simultaneous determination of zinc and nickel in mixtures. The procedure is based on the reaction of zinc and nickel with 2-(2-pyridylmethyleneamino)phenol in buffered 10% v/v methanol-water solutions at pH 8. The determination of nickel and zinc in mixtures in the concentration ranges 0.3-3.0 and 1.0-6.0 mu g ml(-1), respectively, shows good linearity of the calibration graphs. The proposed method was applied to the determination of nickel and zinc in a real bronze sample. The main interferences present in copper alloy were also examined.