Nickel oxide nanoparticles decorated graphene quantum dot as an effective electrode modifier for electrocatalytic oxidation and analysis of clozapine

In the present work, a novel, simple, and sensitive clozapine (CLZ) sensor was developed based on nickel oxide nanoparticle (NiO)-decorated graphene quantum dot (GQD)-modified glassy carbon electrode (NiO/GQD/GCE). NiO/GQD/GCE was prepared by simple electrodeposition, the electrochemical behavior of CLZ at the surface of the prepared electrode was studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), and an improved reversibility and increased peak current with negative shift in the oxidation potential were observed at the proposed electrode. The effect of some experimental parameters has been examined, and based on the results, an electron transfer-chemical reaction-electron transfer mechanism has been proposed for CLZ electrooxidation. The differential pulse voltammetric response of the NiO/GQD/GCE was linear to the concentration of CLZ in the range of 3 x 10(-9) to 1 x 10(-6) M, and the detection limit was found to be 0.55 nM (S/N = 3). The method has been successfully used for the selective determination of the CLZ amount in the pharmaceutical preparations and human serum samples with good accuracy and precision.