Issue 20, 2025

An electrochemical microfluidic sensor based on a Cu2O-GNP nanocomposite integrated hydrogel for nitrite detection in food samples

Abstract

The integration of a nanocomposite composed of cuprous oxide-graphene nanoplatelet hydrogel (Cu2O-GNP hydrogel) has been investigated as an electrochemical interface for nitrite (NO2) detection. The nanocomposite hydrogel was prepared through the sonochemical technique and characterized by Field Emission Scanning Electron Microscopy (FE-SEM), EDX (energy dispersive X-ray analysis), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Electrochemical performance was further evaluated using Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV), and Differential Pulse Voltammetry (DPV). Cu2O provides a catalytic active site that lower the activation energy for NO2 oxidation, while GNPs enhance the electrode conductivity and increase the surface area for superior electron transfer. Additionally, a PDMS-based microfluidic device was developed and integrated with an electrochemical detection system, enabling continuous and real-time monitoring of NO2. A syringe pump was used to maintain a stable NO2 solution flow through the microfluidic channels at a 10 μL per min flow rate, ensuring sufficient diffusion of NO2 ions to the electrode surface, and preventing excess analyte accumulation that could lead to signal distortion. The integrated microfluidic sensor exhibited excellent electrochemical performance, achieving a high sensitivity of 13.97 μA μM−1 cm−2 and a low detection limit (LOD) of 0.56 μM, with a linear range of 5–130 μM. Cu2O-GNP hydrogel/SPCE exhibited excellent selectivity and reproducibility for NO2 sensing. The developed sensor demonstrated good recovery percentages in sausages, pickled vegetables, and water samples, confirming its suitability for the food industry.

Graphical abstract: An electrochemical microfluidic sensor based on a Cu2O-GNP nanocomposite integrated hydrogel for nitrite detection in food samples

Supplementary files

Article information

Article type
Paper
Submitted
28 Jan 2025
Accepted
11 Apr 2025
First published
11 Apr 2025

Anal. Methods, 2025,17, 4124-4137

An electrochemical microfluidic sensor based on a Cu2O-GNP nanocomposite integrated hydrogel for nitrite detection in food samples

D. Kumar, D. Bhatt, D. Garg, V. Kumar, A. Sachdev and I. Matai, Anal. Methods, 2025, 17, 4124 DOI: 10.1039/D5AY00144G

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