A centrifuge-less cloud point extraction-spectrophotometric determination of copper(II) using 6-hexyl-4-(2-thiazolylazo)resorcinol

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 262; p. 120106
• Main Authors: Racheva, Petya V., Milcheva, Nikolina P., Genc, Fatma, Gavazov, Kiril B.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05-12-2021
• Subjects: Azo dye; Cloud point extraction; Copper(II); Green analytical chemistry; Spectrophotometric determination; Cloud point extraction; Spectrophotometric determination; Green analytical chemistry; Azo dye; Copper(II)
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2021.120106

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•A new cloud point extraction-chromogenic system for Cu(II) was studied.•A novel commercially available hydrophobic thiazolylazo dye was used.•The developed procedure is simple, sensitive, economical, and green.•Water samples and a saline solution for infusion were analyzed for Cu(II).
A simple, cheap, and environmentally friendly centrifuge-less cloud point extraction procedure was developed for the preconcentration of traces of Cu(II) before its spectrophotometric determination. It is based on a complexation reaction with the hydrophobic azo reagent 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR), in which a complex with a stoichiometric ratio of 1:1 and an absorption maximum at 535 nm is formed. The experimental conditions for Cu(II) determination were found: HTAR concentration (8 × 10−6 mol mL−1), mass fraction of the surfactant Triton X-114 (2.2%), pH (5.9, ammonium acetate buffer), and incubation time (10 min at 60 °C). The linear range, limit of detection, molar absorption coefficient and preconcentration factor were calculated to be 4.5–254 ng mL−1, 1.34 ng mL−1, 2.54 × 105 L mol−1 cm−1, and 10, respectively. The effect of foreign ions was studied, and the proposed procedure was applied to the analysis of water samples and a saline solution for intravenous infusion.