A rapid, simple extractive spectrophotometric method for the determination of copper, based on the formation of a purple complex between the metal and bis(4-hydroxypent-2-ylidene) diaminoethane is described. The properties of the reagent and some of its colour reactions with other metal ions are reported. The copper complex has an absorption maximum at 540 nm and its molar absorptivity in chloroform is 1.36 x 10(3) 1.mole(-1).cm(-1). Beer’s law is valid up to 384 mug/ml with an optimum working range of 36-334 mug/ml. Job’s method and the molar ratio method indicate 1:2 (metal/ ligand) composition for the complex. The effects of pH, time, temperature, order of addition of reagents, reagent concentration, and interference from various ions are reported. The method is applied to the direct determination of copper in copper-base alloys in the presence of zinc and some other metals without prior separation.
Talanta 12/1980; 27(11 Pt 1):887-91. DOI:10.1016/0039-9140(80)80147-0