Effect of template ion-ligand complex stoichiometry on selectivity of ion-imprinted polymers

Katri Laatikainen; Dutduan Udomsap; Heli Siren; Hugues Brisset; Tuomo Sainio; Catherine Branger

doi:10.1016/j.talanta.2014.11.050

Effect of template ion-ligand complex stoichiometry on selectivity of ion-imprinted polymers

Talanta. 2015 Mar:134:538-545. doi: 10.1016/j.talanta.2014.11.050. Epub 2014 Dec 8.

Authors

Katri Laatikainen¹, Dutduan Udomsap², Heli Siren³, Hugues Brisset², Tuomo Sainio⁴, Catherine Branger⁵

Affiliations

¹ Lappeenranta University of Technology, Laboratory of Separation Technology, P.O. Box 20, FI-53851 Lappeenranta, Finland. Electronic address: Katri.Laatikainen@lut.fi.
² University of Toulon, MAPIEM, EA 4323, 83957 La Garde, France.
³ University of Helsinki, Department of Chemistry, P.O. Box 55, FI-00014 Helsinki, Finland.
⁴ Lappeenranta University of Technology, Laboratory of Separation Technology, P.O. Box 20, FI-53851 Lappeenranta, Finland.
⁵ University of Toulon, MAPIEM, EA 4323, 83957 La Garde, France. Electronic address: branger@univ-tln.fr.

PMID: 25618705
DOI: 10.1016/j.talanta.2014.11.050

Abstract

In order to highlight the importance of the complex stoichiometry during ion imprinted polymer (IIP) synthesis, we investigated the effect of the complex structure on IIPs selectivity by adjusting the complex stoichiometry before polymerization. 2-(aminomethyl)pyridine monomer (amp) was chosen as a functionalized ligand for nickel(II) ions and a polymerizable vinylbenzyl derivative (Vbamp) was prepared. Complex formation was studied by varying the nickel/Vbamp ratio and recording absorption spectra of the complexes at the polymerization conditions. Using a least-squares minimization scheme, the complex species distribution was successfully established. From these results, it was possible to choose the metal/ligand stoichiometry in the complex (1:1; 1:2 or 1:3) by adjusting the initial metal/ligand ratio. IIPs were then prepared by inverse suspension copolymerization of Vbamp with ethyleneglycol dimethacrylate (EDMA). Highly porous particles with good nickel binding capacity and good Ni/Zn selectivity even at acidic conditions were obtained. Equilibrium uptake of Ni(II) at pH 7 ranged from 0.12 to 0.2 mmol g(-1) and relative selective coefficient was as high as 260 for the IIP prepared using the Ni(Vbamp)2 complex.

Keywords: 2-(Aminomethyl)pyridine; Inverse suspension polymerization; Ion imprinted polymers; Nickel.