Sulfadiazine-edaravone azo dye as electrode modifier for carbon paste electrode for simultaneous measurement of paracetamol and folic acid

Aim This work introduces a novel approach by synthesizing a sulfadiazine-edaravone azo dye (SDE) and demonstrating its application in a highly effective electrochemical sensor.Methods The structure of the newly synthesized dye was confirmed through 1H NMR, UV–visible, mass (LC-MS), FT-IR and 13C NMR. The SDE-modified carbon paste electrode (SDE/MCPE) was further employed for the simultaneous voltammetric detection of paracetamol (PA) and folic acid (FA) in phosphate buffer solution (PBS) at pH 7.0. Electrochemical studies, carried out using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV).Results The SDE/MCPE revealed well-defined and distinctly separated oxidation peaks for PA and FA. The electrochemical behavior indicated a diffusion-controlled process with high sensitivity and selectivity. The fabricated sensor exhibited a wide linear detection range between 10 and 70 µM, with limits of detection (LOD) of 6.920 × 10−6 M for PA and 7.235 × 10−6 M for FA, and corresponding limits of quantification (LOQ) of 23.060 × 10−6 M and 24.120 × 10−6 M, respectively. Further, interference studies confirmed the sensor’s selectivity in the presence of potential coexisting species, while EIS analysis verified improved charge-transfer properties of the SDE/MCPE. The reproducibility and stability of the sensor were also evaluated, demonstrating consistent performance and reliable analytical performance.Conclusion Overall, the synthesized SDE dye and the SDE/MCPE exhibit good electrocatalytic behavior, making the sensor highly suitable for sensitive, selective, and reliable simultaneous detection.