Ultrasensitive electrochemical sensor for detection of rutin antioxidant by layered TiAlCuC MAX phase.

MAX phases have attracted great attention due to unique features such as thermal and electrical conductivity, easy fabrication, heat resistant, and lightweight. In this study, an easy and green method was employed to successfully develop a TiAlCuC MAX phase structure, and a TiAlCuC based glassy carbon electrode (GCE) was applied for the electrochemical determination of rutin antioxidants in mandarin and kiwi samples. The developed TiAlCuC MAX phase was characterized by different techniques such as X-ray photoelectron spectroscopy (XPS), thermogravimetry and differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), diffuse reflectance spectroscopy (DRS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) to obtain information on the structural and morphological properties. Electrochemical methods such as cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were employed for the determination of rutin using TiAlCuC/GCE. The GCE modified with TiAlCuC demonstrated amplified electrochemical response (ca. 4.25 times) in comparison to the bare GCE towards rutin, and exhibited ultra-sensitivity and selectivity in the presence of other interfering antioxidants. Under the optimum conditions, good linearity in the range of 0.02-50.00 μmol L was obtained for rutin analysis by the TiAlCuC-based sensor with a limit of detection (LOD, 3σ/K) as low as 0.015 μmol L. The fabricated TiAlCuC MAX phase was applied to determine trace levels of rutin in mandarin and kiwi samples with validation by high-performance liquid chromatography (HPLC), thus highlighting its potential for the electrochemical determination of small molecules in the agricultural field.