Simultaneous third-derivative spectrophotometric determination of copper and nickel in iron alloys and aluminium alloy

A method is proposed for the simultaneous determination of copper and nickel by third-derivative spectrophotometry based on the absorption spectra of their complexes with cyanide ion in the ultraviolet range. The method allows the determination of 0.55-5.8 mug/ml of copper and 0.55-6.8 mug/ml of nickel. The relative standard deviation for 11 determinations of 1.5 mul/ml of copper and nickel were 0.78 and 0.72%, respectively. The detection limits were 0.10,mug/ml for nickel and 0.13 mug/ml for copper. The method has been applied to direct determination of copper and nickel in iron alloys and an aluminium alloy without any separation.