Adsorption-photometric and test-determination of copper in aqueous media using the oxides modified with polyhexamethylene guanidine and bathocuproinedisulfonic acid

Abstract

Adsorbents based on aluminium, zirconium and titanium oxides sequentially modified with polyhexamethylene guanidine (PHMG) and bathocuproinedisulfonic acid (Batocuprsulfo) were proposed for the adsorption-photometric and test-determination of copper in the variant of test tubes. An effective reagent fixation on the surface of inorganic oxides preliminarily modified with PHMG was attained in the range of pH 3-7. The adsorption capacity of the adsorbents for Batocuprsulfo was 22, 11, 7 μmol/g for Al2O3, ZrO2, and TiO2, respectively. Complex compound of Cu(I) with Batocuprsulfo and stoichiometry Cu:Batocuprsulfo=1:2 was formed on the adsorbents surface during Cu(II) adsorption in the presence of reducing agent – hydroxylamine; it was orange colored with maximum at 490 nm in the diffuse reflectance spectra. The quantitative extraction of Cu(I) and the maximum intensity of the surface color of Cu(I) complex was attained from the solutions with pH 6.0–7.0. This effect was used for developing the procedures for adsorption-photometric determination of Cu(I). The most sensitive procedure used aluminium oxide as an adsorbent matrix. The detection limit of Cu(I) determination calculated by the 3s-criterion was 0.02 μg/0.1 g of the adsorbent. The calibration curves were linear over the range of 0.1 - 15.0 μg/0.1 g. The test-procedure for determination of copper by the length of colored area was developed. The minimum determined concentration of copper was 2 μg/L. The proposed methods were used for the determination of Cu(I) in mineral and natural waters. The results obtained were confirmed by the added−found method, and the results of atomic-emission method with inductively coupled plasma.