Novel Electrochemical Sensor based on rGO@TiO2 Composite Material and Ion-Imprinted Polymer Modification for Highly Selective Detection of Cadmium Ions in Real Samples

Abstract Cd(II) has extensive applications in various industries such as electronics, batteries, and coatings, but it is also known as a highly hazardous pollutant. An electrochemical sensor based on ion-imprinted polymers (IIPs) and reduced graphene oxide-titanium oxide (rGO@TiO 2 ) was prepared for the selective sensitive determination of Cd(II) in real samples. The IIPs were prepared using modified SiO 2 as the carrier by surface imprinting technology, which increased the imprinting sites of the polymer and made template ions easy to eluate and improved the electron transfer rate and separation efficiency. The Cd(II) ion-imprinted electrochemical sensor was constructed by mixing IIPs with rGO@TiO 2 in proportion. The morphologies of the imprinted composites were characterized by TEM, FT-IR, and XRD. The electrochemical behavior of imprinted polymers was characterized by CV, DPV, and EIS. The results demonstrated that the sensor has good selectivity for target Cd(II). Under optimized experimental conditions, the electrochemical sensor showed a good linear relationship in the range of 10 − 8 ~ 10 − 5 mol L -1 , and the lowest detection limit was 1.2×10 − 8 mol L -1 . The sensor had excellent repeatability and stability in addition to high sensitivity and strong selectivity. Finally, the electrochemical sensor has been successfully applied to the determination of trace Cd(II) in practical samples.