Impedance and voltammetry detection of bromate in food samples using NiPcMWCNTs modified glassy carbon electrode

Abstract

Abstract A sensitive bromate sensor was developed using nickel phthalocyanine multi-walled carbon nanotubes nanocomposite modified on a glassy carbon electrode. The NiPcMWCNTs nanocomposite was prepared from nickel nanoparticles, phthalocyanine, and functionalized MWCNTs via ultrasonication. UV–visible spectroscopy, SEM, XRD, TEM, and EDX techniques were used to verify the successful fabrication of the nanomaterials. The results of the EIS and CV experiments conducted in 5 mM K3(Fe(CN)6/K4(Fe(CN)6 made in 0.1 M of PBS (pH 7) revealed that the NiPcMWCNTs/GCE exhibited higher current response, faster electron transfer, and high specific capacitance compared to other electrodes. The electrochemical reduction of bromate was actualized in 0.1 M H2SO4 (pH 1) using EIS and SWV techniques. Using the EIS technique, an LoD of 6.72 μM was obtained with a sensitivity of 483.7 μA μM−1 over a linear dynamic range (LDR) of 24–100 μM. Whereas, with the SWV technique, a lower LoD (1.47 μM) was obtained with a higher sensitivity (1293 μA μM−1) over an LDR of 12–56 μM. The developed sensor was characterized by good selectivity, high stability (95.5%), and good reproducibility (% RSD; 3.5%). The fabricated sensor was effectively used to detect bromate in bread samples with a good recovery rate, demonstrating the practical application of the sensor to detect bromate in real samples (bread).

Keywords

• Bromate
• Nickel phthalocyanine
• Multi-walled carbon nanotubes
• Electrochemical sensors
• Electrochemical impedance spectroscopy