Fe3O4/SiO2/CS surface ion-imprinted polymer modified glassy carbon electrode for highly sensitivity and selectivity detection of toxic metal ions

Abstract

A surface ion-imprinting polymer (IIP) based on Fe3O4/SiO2/CS was selected to modify the glassy carbon electrode (Fe3O4/SiO2/CS/Nafion/GCE), and the sensor exhibits ultrasensitive and highly selective to monitor trace level of Cu (II). SiO2 was homogeneously coated on the Fe3O4 magnetic core to enhance the resistance in the harsh environment, especially various acids in the real environment. After that, chitosan film, incorporating copper ions as template ions, covered the Fe3O4/SiO2 and cross-linked with glutaraldehyde. The prepared electrode was used as a working electrode to construct an electrochemical sensor for detecting trace Cu (II) and amplifying the electrochemical signal through the formation of the ion imprinted polymer. The Fe3O4/SiO2/CS/Nafion/GCE IIP based sensors were characterized by XRD, FT-IR, SEM, and TGA. During the electrochemical measurement, different experimental parameters were optimized, and the sensors exhibited a wide linear detection range (0.01 to 20 μmol L−1) and low limit of detection (5 nmol L−1). Besides that, the sensors also demonstrated highly selective to Cu ion, comparing with other interfering ions. The Fe3O4/SiO2/CS/Nafion/GCE-IIP based sensor displayed notable reproducibility and the RSD was 3.3%. The sensors based on Fe3O4/SiO2/CS ion imprinted polymer have the potential to monitor other toxic metal ion pollution in harsh environment.