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

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(HEMA‐MAC)] beads with average size of 63–140 μm were produced by suspension polymerization. After that, the template ions (i.e. Fe³⁺ ions) were removed by 0.1M HCl. Fe³⁺‐imprinted beads were characterized by swelling studies, FTIR, and elemental analysis. The Fe³⁺‐imprinted beads 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 μmol/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%. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3520–3528, 2006