Carbon Paste Electrode Modified with Natural Clay: Electrochemical Study on the Influence of Clay Content for the Detection of Paracetamol and Dopamine

The quantitative and qualitative analysis of pharmaceutical and biological compounds is of growing interest, yet it remains challenging due to the complexity of real sample matrices. Such analysis often requires the simultaneous detection of multiple compounds with high sensitivity and selectivity. In this study, raw Moroccan clay from the Chefchaouen region was used as an additive in different paste matrices for the detection of molecules of biological and environmental importance. Electrochemical techniques, including Cyclic Voltammetry (CV), Differential Pulse Voltammetry (DPV), and Electrochemical Impedance Spectroscopy (EIS), were employed to evaluate the impact of clay incorporation into the composite electrodes. X-ray Diffraction (XRD) analysis revealed the clay contains kaolinite, chlorite, and interstratified illite-smectite, suggesting improved electrochemical performance. An optimal clay content of 3% yielded the highest performance, yielding superior analytical responses compared to other tested proportions. The developed sensor shows strong potential for future use in the simultaneous detection of Paracetamol (PAR) and Dopamine (DA), particularly in real samples such as pharmaceutical tablets and biological fluids like urine.