A new chelating resin: Synthesis, characterization and application for speciation of chromium (III)/(VI) species

A new method for speciation, preconcentration and separation of Cr(III) and Cr(VI) in different matrices was developed using solid phase extraction and flame atomic absorption spectrometry (FAAS). Poly-2-(5-methylisoxazole) methacrylamide-co-2-acrylamido-2-methyl-1-propanesulfonic acid-co-divinylbenzene) (MAD), was synthesized and characterized as a new chelating resin for the speciation of Cr(III)/Cr(VI) species. Cr(III) was quantitatively recovered on chelating resin at pH range of 1.5–4.5, while Cr(VI) was not quantitatively recovered in all the pH's. The optimum conditions for the speciation of Cr(III)/Cr(VI) species were investigated on several commonly tested experimental parameters such as pH of the solution, amount of the resin, sample volume, and interfering ions. The preconcentration factor was found to be 200. The limit of detection for Cr(III) corresponding to three times the standard deviation of the blank (3 s) was found 0.01 μg L−1. Adsorption capacity and binding equilibrium constant were calculated to be 34.3 mg g−1 and 1.5 L mg−1, respectively. The method was validated by analysing certified reference materials. The proposed method was applied to the determination and speciation of chromium species in various water and food samples with satisfactory results.

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► A new chelating resin was firstly synthesized for speciation of Cr(III) and Cr(VI) species, and was characterized.
► High adsorption capacity (34.3 mg g−1), high preconcentration factor (200), low detection limit (0.01 μg L−1).
► The proposed method was applied to speciation of chromium species in various water and food samples with satisfactory results.