Application of Chitosan and the Green Synthesized NiO-Bi2O3 Nanocomposite in Modification of Glassy Carbon Electrode for Simultaneous Determination of p-Nitrophenol and o-Nitrophenol

Abstract A solventless method was used to prepare NiO nanoparticles (NPs) while an aqueous extract from banana peels was used to green synthesize Bi2O3 NPs. Characterization of the resulting samples indicated the formation of pure mesoporous NiO and Bi2O3 NPs with crystallite sizes of 23 and 3.1 nm, respectively. A glassy carbon electrode (GCE) was modified by applying chitosan (CS) along with NiO and Bi2O3 NPs. The fabricated NiO-Bi2O3/CS/GCE sensor was applied for the simultaneous determination of p-nitrophenol (p-NP) and o-nitrophenol (o-NP) using cyclic, linear sweep, and differential pulse voltammetry. p-NP showed excellent behavior in PBS electrolyte at pH 7.0 and a 100 mV/s scan rate. The calculated limits of detection and quantitation and linear range were 23.8, 79.5, and 0.1-100 nM, respectively. The sensor demonstrated high selectivity (less than 5% change in the presence of various interferences), reproducibility (2.43% RSD), and stability (98.35% after one month). Finally, the sensor had successfully estimated p-NP in tap and wastewater samples.