Polystyrene-divinyl benzene microspheres with amino methyl phosphonic acid functional hairy brushes for the sorption and speciation of chromium prior to inductively coupled plasma mass spectrometric determination.

This article describes the synthesis and application of a novel sorbent for Cr(III) and Cr(VI) speciation prior to their quantitation by inductively coupled plasma mass spectrometry. The sorbent consists of polystyrene-divinyl benzene microbeads that were graft-coated with poly(oligo (ethylene glycol) methacrylate)-block-poly(glycidyl methacrylate). The particles were finally modified with phosphomethylated triethylene tetramine. The resulting microbeads are shown to be a viable sorbent for Cr(VI). The total concentration of chromium was determined after oxidation of Cr(III) to Cr(VI) with KMnO4 using the novel sorbent. The Cr(III) amount was then calculated by subtracting the concentration of Cr(VI) from that of total chromium. The optimum conditions for batch type sorption were established. Under optimal conditions, the limit of detection and quantification are 0.015 µg L-1 and 0.050 µg L-1, respectively. The kinetics and isotherms of the sorption of Cr(VI) were investigated. Following desorption with 0.1 M hydroxylamine hydrochloride, the method was successfully applied to spiked real water samples and a certified reference material. Graphical abstract Schematic presentation of a method for the sorption and speciation of chromium using amino methyl phosphonic acid functional brushes on polystyrene-divinyl benzene microspheres.