Determination of copper in urine by diffuse reflectance spectroscopy

A possibility of determining copper(II) after adsorption on polyacrylonitrile fiber filled with a KU-2 cation exchanger with immobilized 1-(2-pyridylazo)-2-naphthol (PANF–KU-2–PAN) is studied. The diffuse reflectance spectra of the carrier discs before and after the adsorption of copper in the batch mode are recorded. The dependences of the analytical signals of the copper complex on PANF–KU-2–PAN on adsorption conditions are studied. The conditions for determining 0.05–0.40 μg/mL of copper(II) by measuring diffuse reflection coefficient at 640 nm or visually by a color scale after the adsorption of copper from 20 mL of a solution containing 0.01 M of HCl are found. The determination of 0.1 μg/mL of copper does not interfered with equal amounts of Co, Zn, and Pb and double amounts of Ag, Fe(III), Cd, Mn(II), Bi(III), and Cr(III). The procedure is used for urine analysis. The following conditions of the preparation of urine samples for the determination of copper were selected: boiling with hydrogen peroxide followed by acidification to pH 2. A procedure for determining copper in urine with a limit of detection of 0.03 μg/mL was developed; the relative standard deviation does not exceed 25%; the duration of analysis of 5–6 samples is 30–35 min.