Green voltammetric strategy for sensitive determination of paracetamol in pharmaceuticals and serum using alizarin red S-modified glassy carbon electrodes

This study introduces a highly sensitive electrochemical method for detecting paracetamol (PCT) in pharmaceutical tablets and human serum samples, utilizing a glassy carbon electrode modified with alizarin red S (poly (ARS)/GCE). PCT is one of the most widely used analgesic and antipyretic drugs; however, its overdose or prolonged use can lead to severe liver and kidney damage. Therefore, the development of sensitive and reliable methods for monitoring PCT levels in pharmaceutical formulations and biological fluids is crucial for ensuring drug safety and effective therapeutic monitoring. Characterization of the electrode confirmed that the surface modification with a conductive and electroactive polymer film (poly(ARS)) significantly enhanced the effective electrode surface area and reduced charge transfer resistance. Compared to the unmodified electrode, the modified electrode exhibited a well-resolved, irreversible redox peak at a significantly lower potential with a sixfold increase in current, highlighting the catalytic efficiency of the modifier toward PCT. The electrochemical behavior of PCT was analyzed via cyclic voltammetry and square wave voltammetry, revealing significantly enhanced sensitivity and selectivity due to the conductive polymer coating. Under optimized electrode condition square wave voltammetric current response of poly(ARS)/GCE showed linear dependence on concentration of 0.01–250.0 μM and an ultralow detection limit of 1.0 nM in phosphate buffer solution (pH 7.0). Analytical application on real samples confirmed the method's accuracy, achieving recovery rates of 98.8–100.3 % for pharmaceutical tablets and human blood serum, even in the presence of potential interferents. The developed method provides a cost-effective and robust alternative for PCT quantification, with superior performance compared to previously report electrochemical approaches.