Iron(II) ion imprinted polymer for Fe(II)/Fe(III) speciation in wine

In this paper, we proposed a procedure for the determination of Fe(III) and total Fe(II) + Fe(III) in wine samples employing newly synthesized Fe(II) ion imprinted polymer (Fe(II)-IIP) as a sorbent incorporated in dispersive solid phase extraction. Cross-linked precipitation copolymerization using 4-vinylpyridine (functional monomer), trimethylolpropane trimethacrylate (cross-linking agent) and 2,2'-bipyridyl as a specific for Fe(II) ligand was used for the synthesis of Fe(II)-IIP. The optimization experiments showed quantitative sorption of both Fe(II) and Fe(III) on the surface of Fe(II)-IIP at pH 7, however selective sorption of only Fe(II) could be achieved in the presence of fluoride ions as a masking agent for Fe(III). The Langmuir adsorption isotherm best described the adsorption of Fe(II) on the surface of the sorbent on the at least two kinds of binding sites with higher and lower affinities as defined by Scatchard plot The analytical procedure developed allows the determination of iron(III) and total Fe(II) + Fe(III) in wine samples, with limits of quantification 0.1 mg L-1. The relative standard deviation varied in the range 3-7% for Fe content 0.1-10 mg L-1. (C) 2017 Elsevier B.V. All rights reserved.