Modification of the electrochemical sensor with NiCo₂O₄ decorated graphene composite electrode for sulphite determination in food samples

In order to accurately determine the amount of sulphite in food samples, this study focuses on the fabrication and modification of electrochemical sensors employing NiCo₂O₄ adorned graphene composite electrodes. The glassy carbon electrode (GCE) was modified using a drop-casting technique using a NiCo₂O₄/reduced graphene oxide (rGO) nanocomposite (NiCo₂O₄/rGO/GCE). SEM, XPS, XRD, CV, and amperometry investigations were used to characterize the structural and electrochemical properties. The results of the analyses validated the nanocomposite’s effective synthesis and its potential for improved electrochemical performance as a result of the interaction between rGO and NiCo₂O₄. After adding sulphite, the modified electrode showed a noticeable reduction in peak current, indicating effective catalysis. The sensor was found to have a sensitivity of 0.32341 µA/µM, a limit of quantification (LOQ) of 12 nM, and a limit of detection (LOD) of 3 nM. In terms of recovery rates for sulphite, NiCo₂O₄/rGO/GCE showed strong selectivity, reproducibility, and stability; the relative standard deviation (RSD) ranged from 3.22 to 4.73%. According to good recovery rates and RSD values in real sample tests, the NiCo₂O₄/rGO composite sensor shows increased sensitivity and specificity, making it a suitable option for real-world applications in food sample sulphite detection.