Synthesis of multidentate functional monomer for ion imprinting

In this work, N,N,N ‐tri(2‐carboxyethyl)‐3‐(2‐aminoethylamino)propyl‐trimethoxysilane was prepared as a multidentate functional monomer. The 3D model of the monomer coordinating with Cu 2+ indicated that the monomer is able to provide five ligating atoms like ethylenediaminetetraacetic acid‐Cu 2+ to complex with Cu 2+ . When Cu 2+ was used as a template ion, the synthesis conditions of Cu 2+ ‐imprinted polymers were optimized upon orthogonal design. It is interesting to find that Cu 2+ ‐imprinted polymer offers a selectivity coefficient of 192.2 when the molar ratio of Cu 2+ to monomer was exactly 1:1. That means there is no excess ligating atom in the ion‐imprinted polymer and therefore, the nonspecific adsorption could be avoided. Benefiting from the excellent selectivity of Cu 2+ ‐imprinted polymer, even if the concentration of Zn 2+ was 25 times that of Cu 2+ , Cu 2+ ‐imprinted polymer still affords a high selectivity coefficient. Finally, the optimal synthesis conditions for Cu 2+ ‐imprinted polymer, except the pH, were adopted to prepare Ni 2+ ‐imprinted polymer, and Ni 2+ ‐imprinted polymer also offered satisfying selectivity to Ni 2+ . That implies this multidentate monomer is adaptable in ion imprinting and, the optimal synthesis conditions of Cu 2+ ‐imprinted polymer except pH are likely suitable for the imprinting of other ions besides Cu 2+ .