Removal of iron by chelation with molecularly imprinted supermacroporous cryogel

Abstract

Iron chelation therapy can be used for the selective removal of Fe³⁺ ions from spiked human plasma by ion imprinting. N-Methacryloyl-(L)-glutamic acid (MAGA) was chosen as the chelating monomer. In the first step, MAGA was complexed with the Fe³⁺ ions to prepare the precomplex, and then the ion-imprinted poly(hydroxyethyl methacrylate-N-methacryloyl-(L)-glutamic acid) [PHEMAGA-Fe³⁺] cryogel column was prepared by cryo-polymerization under a semi-frozen temperature of − 12°C for 24 h. Subsequently, the template, of Fe³⁺ ions was removed from the matrix by using 0.1 M EDTA solution. The values for the specific surface area of the imprinted PHEMAGA-Fe³⁺ and non-imprinted PHEMAGA cryogel were 45.74 and 7.52 m²/g respectively, with a pore size in the range of 50–200 μm in diameter. The maximum Fe³⁺ adsorption capacity was 19.8 μmol Fe³⁺/g cryogel from aqueous solutions and 12.28 μmol Fe³⁺/g cryogel from spiked human plasma. The relative selectivity coefficients of ion-imprinted cryogel for Fe³⁺/Ni²⁺ and Fe³⁺/Cd²⁺ were 1.6 and 4.2-fold greater than the non-imprinted matrix, respectively. It means that the PHEMAGA-Fe³⁺ cryogel possesses high selectivity to Fe³⁺ ions, and could be used many times without significantly decreasing the adsorption capacity.