Simultaneous spectrophotometric determination of trace amounts of cobalt, nickel, and copper using the partial least-squares method after the preconcentration of their 2-aminocyclopentene-1-dithiocarboxylate complexes on microcrystalline naphthalene

A spectrophotometric method for the determination of trace amounts of cobalt(II), nickel(II), and copper(II) after the adsorption of their 2-aminocyclopentene-1-dithiocarboxylate complexes on microcrystalline naphthalene has been developed. These complexes are adsorbed on microcrystalline naphthalene at pH 4.5 by shaking for 5 min. The formed solid mass is separated by filtration, and dissolved in dimethylformamide. The absorption spectra were processed using the partial least-squares multivarate calibration method for the analysis of a ternary mixture of Co(II), Ni(II), and Cu(II). The detection limits for Co(II), Ni(II), and Cu(II) were 3.3, 10.0, and 0.8 ng/mL, respectively. The total relative standard error for applying the method to 20 synthetic samples in the concentration ranges of 20–400 ng/mL Co(II), 60–400 ng/mL Ni(II), and 4–400 ng/mL Cu(II) was 1.53%. The proposed method was also successfully applied to the determination of Co(II), Ni(II), and Cu(II) in alloys. The text was submitted by the authors in English.