Environmental method for spectrophotometric determination of copper(II)

A highly stable ternary complex of copper(II) with 5-(4-nitrophenylazo) salicylic acid (NPAS) and 2,2′-Dipyridyl (Dp) in ethanol medium at room temperature gave a maximum absorption at 520 nm with a molar absorptivity 2.60×10 ⁴ L mol ^-1 cm ^-1. This method was characterized by safety to the environment as there are no uses of hazardous solvents, which may harm our environment. The linear range for copper determination was 2.2-6.3 mg L ^-1. The method was sensitive, accurate, and tolerant to many foreign ions. All the reagents were stable under the working conditions. Moreover, the method was easy to perform for the determination of copper in pharmaceutical, biological, and water samples.