Simultaneous Determination of Cu and Ni in Drinking Water Using a Homemade Device Based on an Internet-Controlled Smartphone Camera

A simple protocol for the resolution of a Cu2+ and Ni2+ mixture in drinking water is proposed as a laboratory work to teach the digital colorimetric applications in analytical chemistry. The didactic strategy followed in this exercise starts with a clearly defined problem and the students have to learn the chemical principles involved. After, they design the necessary devices to acquire digital images for further treatment with adequate software, in order to obtain the RGB values needed to calculate the absorbance values. Once reliable experimental data is obtained regression equations for single ions were calculated and the absorbance additivity was checked. These equations were employed to determine simultaneously the concentrations of Cu2+ and Ni2+ in real water samples provided by the instructor.