A rapid and reliable electrochemical determination of 5- hydroxymethylfurfural in honey exploiting nickel oxide nanoparticles modified electrode

This study presents a novel approach for the rapid and reliable electrochemical determination of 5-hydroxymethylfurfural (5-HMF) in honey using a screen-printed carbon electrode modified with nickel oxide nanoparticles (NiONPs/SPCE). The NiONPs were synthesized using a simple method and characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The NiONPs/SPCE demonstrated enhanced sensitivity and selectivity for 5-HMF detection. The electrochemical behavior of 5-HMF on the NiONPs/SPCE was investigated using techniques such as cyclic voltammetry (CV) and square wave voltammetry (SWV). The optimum experimental conditions were obtained including a 5 μL of 5.0 mg/mL NiONPs modifier, the voltammetric response of step potential 15 mV, amplitude 50 mV and frequency 50 Hz in 0.1 M BR buffer pH 13 as supporting electrolyte. The proposed method exhibited a linear relationship between the cathodic peak current and the concentration of 5-HMF in the concentration ranges of 0.5-5.0 ppm, with a limit of detection (LOD) of 0.24 ppm. The selectivity of the NiONPs/SPCE was evaluated by studying potential interferences commonly found in honey samples, and the results demonstrated excellent selectivity for 5-HMF detection. The reproducibility and stability of the NiONPs/SPCE were also assessed, with low relative standard deviations (RSD) obtained for both the cathodic peak current (2.94 %) and long-term stability (3.14 %). The developed NiONPs/SPCE method was successfully applied to the determination of 5-HMF in real honey samples, yielding comparable results to the standard HPLC method. This work showcases the potential of the NiONPs/SPCE as a practical and cost-effective electrochemical sensor for the accurate analysis of 5-HMF in honey samples.