Carbon-modified kaolin clay using sugar dehydration technique for the electrochemical detection of quercetin

Herein, we report a simple strategy to modify kaolin clay with carbon as an electrocatalyst for quercetin detection. The modified clay composite was characterized using X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Electrochemical impedance spectroscopy (EIS) was used to analyze the electron transfer process of the carbon-modified electrode. The electro-oxidation behavior of quercetin was studied using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. CV experiments displayed that the electro-oxidation behavior of C-kaolin composite was significantly enhanced than unmodified kaolin clay. Under the optimized conditions, the prepared sensor showed increasing linear concentration in the range from 0.12 to 182.1 µM with the detection limit (LoD) of 0.057 µM (S/N = 3). The proposed sensor was applied for the detection of QCN in apple juice and the recovery percentage was found to be 93 to 97%. Thus, the proposed sensor is simple, cost-effective, and can be utilized for several analytical applications.