Voltammetric detection of paracetamol using a novel Sonogel-Carbon material modified with monocalcium phosphate: An experimental and theoretical approach

Abstract

A highly sensitive and selective electrochemical sensor was developed by modifying a sonogel-carbon electrode with monocalcium phosphate (MCP/SNGCE) for the first time detection of paracetamol (PCT). The sensor electrochemical properties were characterized using electrochemical impedance spectroscopy and cyclic voltammetry. MCP incorporation into the silica network increased the electroactive surface area by ~45 % and reduced charge transfer resistance by 39 % compared to the unmodified electrode, enhancing electron transfer at the electrode/solution interface. Surface characterization confirmed successful MCP integration, indicated by a characteristic X-ray diffraction peak at 7.52° and a shift in the Si-CH₃ band from 760 cm⁻¹ (SNGCE) to 765 cm⁻¹ (MCP/SNGCE) in the Fourier-transform infrared spectroscopy, reflecting improved electrocatalytic activity towards PCT oxidation. Differential pulse voltammetry revealed a linear detection range for PCT from 0.05 μM to 24 μM, with a detection limit of 0.01 μM. The sensor exhibited high sensitivity (36.541 μA cm⁻² μM⁻¹), excellent repeatability, reproducibility with a relative standard deviation (RSD) <4 %, and stable performance over 30 days. Theoretical approaches and Monte Carlo simulations and topological analyses provided further insights, showing PCT adsorbs inclined on the MCP surface via semi-covalent interactions between hydrogen atoms H19 (-CH₃ group) and H13 (benzene ring), with a maximum interaction energy of −1427 kcal mol⁻¹. The sensor was successfully applied to PCT detection in tap water, pharmaceutical tablets, and simulated blood serum, achieving recovery rates of 98.1–104 %, 97.78–105.61 %, and 100.15–102.5 %, respectively.