Preparation, Characterization, and Electrochemical Application of Ni0.₉₆O‐Porous Reduced Graphene Oxide Nanocomposite for Catecholamines

Abstract A novel method of preparation was followed to obtain nickel oxide (Ni 0.96 O) nanoparticles using Amorphophallus konja leaf extract by combustion method. The porous reduced graphene oxide (prGO) was synthesized by the low‐temperature solution combustion method. The prGO and Ni 0.96 O NPs were combined to obtain a Ni 0.96 O‐prGO nanocomposite by simple sonication method. The formation of Ni 0.96 O‐prGO nanocomposite was confirmed by XRD. The results of SEM and AFM were used to understand the surface morphology and its properties. This material was utilized to prepare a sensor and study electrochemical sensing of catecholamines viz; dopamine (DA), methyldopa (MD), and levodopa (LD). The proposed differential pulse voltammetric (DPV) method showed linearity in the concentration range of 0.03–112.2 µΜ, 0.01–124.5 µΜ, and 0.05–76.5 µΜ for DA, MD, and LD, respectively. The limit of detection (LOD) was calculated to be 0.028, 0.011 and 0.031 µΜ while the limit of quantification (LOQ) was found to be 0.095, 0.037 and 0.103 µΜ for DA, MD, and LD, respectively with the DPV method. The developed methods were successfully applied for the determination of DA, MD, and LD in pharmaceutical formulations and human urine samples. The proposed electrochemical sensor showed excellent reproducibility, selectivity, and repeatability for catecholamines.