An Electroanalytical Enzymeless α-Fe2O3-ZnO Hybrid Nanostructure-Based Sensor for Sensitive Quantification of Nitrite Ions

Rafiq Ahmad; Abdullah; Md Tabish Rehman; Mohamed F AlAjmi; Shamshad Alam; Kiesar Sideeq Bhat; Prabhash Mishra; Byeong-Il Lee

doi:10.3390/nano14080706

An Electroanalytical Enzymeless α-Fe₂O₃-ZnO Hybrid Nanostructure-Based Sensor for Sensitive Quantification of Nitrite Ions

Nanomaterials (Basel). 2024 Apr 18;14(8):706. doi: 10.3390/nano14080706.

Authors

Rafiq Ahmad^{1

2}, Abdullah³, Md Tabish Rehman⁴, Mohamed F AlAjmi⁴, Shamshad Alam⁵, Kiesar Sideeq Bhat⁶, Prabhash Mishra⁷, Byeong-Il Lee^{8

9

10}

Affiliations

¹ 'New-Senior' Oriented Smart Health Care Education Center, Pukyong National University, Busan 48513, Republic of Korea.
² Centre for Nanoscience and Nanotechnology, Jamia Millia Islamia (Central University), Jamia Nagar, New Delhi 110025, India.
³ Future Energy Convergence Core Center, Jeonbuk National University, Jeonju 54896, Republic of Korea.
⁴ Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.
⁵ Department of Pharmacology & Therapeutics, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.
⁶ Department of Bioresources, University of Kashmir, Hazratbal, Srinagar 190006, India.
⁷ Quantum Materials and Devices Laboratory, Faculty of Engineering and Technology, Jamia Millia Islamia (Central University), Jamia Nagar, New Delhi 110025, India.
⁸ Industry 4.0 Convergence Bionics Engineering, Pukyong National University, Busan 48513, Republic of Korea.
⁹ Digital Healthcare Research Center, Institute of Information Technology and Convergence, Pukyong National University, Busan 48513, Republic of Korea.
¹⁰ Division of Smart Healthcare, College of Information Technology and Convergence, Pukyong National University, Busan 48513, Republic of Korea.

Abstract

Nitrite monitoring serves as a fundamental practice for protecting public health, preserving environmental quality, ensuring food safety, maintaining industrial safety standards, and optimizing agricultural practices. Although many nitrite sensing methods have been recently developed, the quantification of nitrite remains challenging due to sensitivity and selectivity limitations. In this context, we present the fabrication of enzymeless iron oxide nanoparticle-modified zinc oxide nanorod (α-Fe₂O₃-ZnO NR) hybrid nanostructure-based nitrite sensor fabrication. The α-Fe₂O₃-ZnO NR hybrid nanostructure was synthesized using a two-step hydrothermal method and characterized in detail utilizing x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). These analyses confirm the successful synthesis of an α-Fe₂O₃-ZnO NR hybrid nanostructure, highlighting its morphology, purity, crystallinity, and elemental constituents. The α-Fe₂O₃-ZnO NR hybrid nanostructure was used to modify the SPCE (screen-printed carbon electrode) for enzymeless nitrite sensor fabrication. The voltammetric methods (i.e., cyclic voltammetry (CV) and differential pulse voltammetry (DPV)) were employed to explore the electrochemical characteristics of α-Fe₂O₃-ZnO NR/SPCE sensors for nitrite. Upon examination of the sensor's electrochemical behavior across a range of nitrite concentrations (0 to 500 µM), it is evident that the α-Fe₂O₃-ZnO NR hybrid nanostructure shows an increased response with increasing nitrite concentration. The sensor demonstrates a linear response to nitrite concentrations up to 400 µM, a remarkable sensitivity of 18.10 µA µM^-1 cm^-2, and a notably low detection threshold of 0.16 µM. Furthermore, its exceptional selectivity, stability, and reproducibility make it an ideal tool for accurately measuring nitrite levels in serum, yielding reliable outcomes. This advancement heralds a significant step forward in the field of environmental monitoring, offering a potent solution for the precise assessment of nitrite pollution.

Keywords: enzymeless; hybrid nanostructure; iron oxide nanoparticle; nitrite; sensitive sensor; zinc oxide nanorod.

Grants and funding

This work was supported by the Department of Biotechnology (DBT; Project number: BT/RLF/Re-entry/28/2018), Government of India. M.T.R. and M.F.A. acknowledge the generous support from the Researchers Supporting project number (RSP 2024R122), King Saud University, Riyadh, Saudi Arabia.