Simultaneous Electrochemical Detection of Puerarin and Daidzein by Ag Nanoparticles and CuO Nanowires Coated ZnO Nanorod Arrays Self-Supporting Electrode

In this study, ZnO nanorods (ZnONR) were directly grown on carbon fiber paper (CFP), followed by the uniform chemical deposition of CuO nanowires (CuONW) and subsequent hydrothermal synthesis of Ag nanoparticles (AgNP) to form the ternary composite electrode AgNP-CuONW/ZnONR@CFP. When the prepared electrodes were investigated as a non-enzyme biosensor, two distinct and separated differential pulse voltammetric peaks for puerarin (PU) and daidzein (DAI) were observed, indicating that the simultaneous and selective detection of both isoflavones was feasible. The sensor exhibited a linear response across a broad concentration range of 0.01 to 30 μmol/L for puerarin (PU) and 0.05 to 15 μmol/L for daidzein (DAI), with detection limits of 4.0 nmol/L for PU and 17.8 nmol/L for DAI, respectively. Additionally, when used to detect puerarin (PU) and daidzein (DAI) in traditional Chinese medicine samples, the sensor performed excellently, yielding results that consistent with those obtained from high-performance liquid chromatography (HPLC) analysis.