Inorganic Oxides with Immobilized Ferrozine and Ferene for the Sorption–Spectroscopic Determination of Iron(II)

Abstract

Sorbents based on inorganic oxides sequentially modified with polyhexamethylene guanidine, ferrozine, and ferene S are proposed for the preconcentration and determination of iron(II). Upon sorption from solutions with pH 2.5–7.0, colored iron(II) complexes with ferrozine and ferene S, having broad bands with maxima at 560 and 600 nm in the diffuse reflectance spectrum, respectively, formed on the sorbent surface. Procedures for the sorption–photometric determination of iron(II) using diffuse reflectance spectroscopy were developed. The limits of detection for iron(II), calculated by the 3s criterion were 0.005 and 0.006 μg per 0.1 g for sorbents based on silica with immobilized ferrozine and ferene S, respectively. The linearity of calibration curves remains up to 5 and 10 μg per 0.1 g for sorbents based on silicon and aluminum oxides, respectively. The procedures were tested in the determination of the total iron concentration in bottled drinking waters and alcoholic drinks.