Electrochemical Detection of Paracetamol in Real Samples Using Sensor Based on a Glassy Carbon Electrode Modified with Chitosan@SiO₂-APTES Composite: Synthesis, Characterization and Analytical Applications

Paracetamol (PA), commonly known as acetaminophen, is used for a variety of therapeutic applications. However, excessive or inappropriate use can lead to liver and kidney damage, emphasizing the importance of accurate measurement of its concentration in biological samples. In this study, we developed a rapid, simple, and highly sensitive voltammetric method using chemically-modified electrodes to detect PA in complex matrices such as human serum and commercial solid formulations. A glassy carbon electrode was modified with a chitosan-silica nanoparticle composite functionalized with 3-aminopropyltriethoxysilane groups (chitosan@SiO₂-APTES). The properties of the modified electrode and PA detection were analyzed using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Kinetic studies provided further insight into the electrochemical behavior of the electrode and improved its characterization. With this method, detection and quantification limits of only 0.025 μM were achieved under optimized conditions. Furthermore, it was found that the ideal linear concentration range for PA detection is between 0.025 and 0.5 μM and between 0.5 and 2.5 μM. Thus, this approach is ideal for the accurate quantification of PA in reference tablet formulations and for the analysis of real samples for validation purposes.