A Sensitive Electrochemical Sensor Based on Ion Imprinted Polymers with Gold Nanoparticles for High Selective Detecting Cd (II) Ions in Real Samples

A novel electrochemical sensor based on ion imprinted polymers and gold nanoparticles was fabricated for selective and sensitive determination of Cd (II) ion in real samples. Ion imprinted polymers synthesized by conventional precipitation polymerization methods may have the problem in embedding the imprinting sites too deeply. Thereby, the surface imprinting technology by attaching the imprinted material on the surface of the silicon sphere was used to increase the quantity of the imprinting site, and enhances the adsorption performance of the imprinted material. Moreover, thiosemicarbamide functionalized chitosan and methacrylic acid were selected as functional monomers to synthesize the ion imprinted polymers, which enhanced the coordination ability of Cd (II) ions. Also, the electrochemical performance of the electrochemical sensor was well improved by doping gold nanoparticles in the polymer. The morphologies of the obtained imprinted composites were characterized by scanning electron microscopy, transmission electron microscopy. The electrochemical behavior of the imprinted polymers was characterized by CV, DPV and EIS. As a result, the fabricated sensor showed a good selectivity toward target Cd (II) ions. Under optimized experimental conditions, the electrochemical sensor showed a good linear relationship in the range of 10–9 to 10–4 mol/L with a low limit detection of 1.43 × 10–10 mol/L. The improved sensor not only possesses good selectivity and high sensitivity, but also exhibits excellent repeatability and stability. Finally, the proposed electrochemical sensor was successfully applied to the determination of trace Cd (II) ions in real samples.