Binding behavior of Fe3+ ions on ion-imprinted polymeric beads for analytical applications

Abstract

We used a molecular imprinting approach to achieve specific metal binding utilizing N-methacryloyl-(L)cysteine methyl ester (MAC) as a metal-complexing ligand. MAC was synthesized using methacryloyl chloride and cysteine methyl ester. Then, Fe3+ was complexed with MAC monomer. Fe3+-imprinted poly(hydroxyethyl methacrylate-N-methacryloyl-(L)-cysteine methyl ester) [poly(HEMAMAC)] beads with average size of 63-140 gm were produced by suspension polymerization. After that, the template ions (i.e. Fe3+ ions) were removed by 0.1M HCI. Fe3+- imprinted beads were characterized swelling studies, FTIR, and elemental analysis. The Fe3+-imprinted beads FTIR, and elemental analysis with a swelling ratio of 72%, and containing 3.9 mmol MAC/g were used in the binding of Fe3+ ions from aqueous solutions, tap water, certified reference serum sample, and real serum sample. Maximum binding capacity, optimum pH, and equilibrium binding time were 107 mu mol/g, pH 3.0, and 30 min, respectively. It was observed that even in the presence of other ions, Fe3+-imprinted beads selectively bound Fe3+ ions with 97% efficiency. Removal of Fe3+ ions from certified reference serum sample was approximately found to be 33%