Co3O4-CeO2/Graphene Composite as a Novel Sensor for Amaranth Detection

Abstract

Amaranth is widely used in food industry, its daily intake is 0–1.5 mg kg−1. Excessive consumption of amaranth may have many adverse effects to health. So it is very important to accurately determine the content of amaranth in food. Graphene (Gr) and Co3O4-CeO2 were prepared by electrolysis and hydrothermal method, respectively. Co3O4-CeO2/Gr nanocomposite was physically grinded by the above two materials for amaranth detection. The structure, morphology and valence state of as-prepared composite were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to detect the response of amaranth. Under the optimal conditions, the oxidation peak current of amaranth increases proportionally with its concentration in the range of 2–96 μM. The sensitivity was 0.8642 μA μM−1 cm−2 and the detection limit was 0.1591 μM. The proposed Co3O4-CeO2/Gr modified electrode as electrochemical sensor has a wide linear range, high sensitivity, good repeatability, stability, and anti-interference ability, which can be used to determine successfully the content of amaranth in soft drinks.