Synthesis and characterization of novel ion-imprinted polymeric nanoparticles for very fast and highly selective recognition of copper(II) ions

This work reports the preparation of new Cu2+ ion-imprinted polymeric nanoparticles using 1-hydroxy-4-(prop-2′-enyloxy)-9,10-anthraquinone (AQ) as a vinylated chelating agent. The Cu2+ ion found to form a stable 1:1 complex with AQ in methanol solution. The resulting Cu2+–AQ complex was copolymerized with ethyleneglycol dimethacrylate, as a cross-linking monomer, via precipitation polymerization method. The imprint copper ion was removed from the polymeric matrix using a 0.1 mol L−1 HNO3 solution. The Cu2+-imprinted polymeric nanoparticles were characterized by IR spectroscopy, scanning electron microscopy (SEM) and N2 adsorption–desorption isotherms. The SEM micrographs showed colloidal nanoparticles of 60–100 nm in diameter and slightly irregular in shape. Optimum pH for maximum sorption was 7.0. Sorption and desorption of Cu2+ ion on the IIP nanoparticles were quite fast and achieved completely over entire investigated time periods of 2–30 min. Maximum sorbent capacity and enrichment factor of the prepared IIP for Cu2+ were 73.8 μmol g−1 and 56.5, respectively. The relative standard deviation and limit of detection (CLOD = 3Sb/m) of the method were evaluated as 2.6% and 0.1 ng mL−1, using inductively coupled plasma-atomic emission spectrometry, respectively. It was found that the imprinting technology results in increased affinity of the prepared material toward Cu2+ ion over other metal ions with the same charge and close ionic radius. The relative standard deviations for six and twenty replicates with the same nanoparticles were found to be 1.7% and 2.1%, respectively.