Hierarchical Ni-rGO nanocomposite derived from e-waste graphite for trace-level electrochemical sensing of metronidazole.
4 affiliations
- 1Institute of National Analytical Research and Service (INARS), Bangladesh Council of Scientific and Industrial Research (BCSIR) Dhanmondi Dhaka-1205 Bangladesh [email protected].
- 2Department of Chemistry, University of Dhaka Dhaka-1000 Bangladesh.
- 3Institute of Food Science and Technology (IFST), Bangladesh Council of Scientific and Industrial Research (BCSIR) Dhanmondi Dhaka-1205 Bangladesh [email protected].
- 4Institute of Energy Research & Development (IERD), Bangladesh Council of Scientific and Industrial Research (BCSIR) Dhanmondi Dhaka-1205 Bangladesh.
Abstract
Metronidazole (MTZ) accumulation in aquatic systems presents severe environmental and public health risks, requiring sensitive trace-level monitoring techniques. Here, we report the development of an electrochemical sensor based on a reduced graphene oxide (rGO) nanocomposite decorated with nickel-containing nanophases (Ni-rGO). The graphene oxide support was synthesized from graphite sustainably recovered from discarded lithium-ion batteries prior to integration via a one-pot, hydrazine-free hydrothermal method. Morphological and structural analyses (SEM, TEM, XRD, FTIR) reveal a hierarchical architecture where highly dispersed, ultra-small (1.5-3 nm) nickel-containing domains coexist with larger crystalline domains anchored to a porous rGO network. This dual-scale structure likely prevents graphene restacking, resulting in a 41.2% increase in electrochemically active surface area and a 43.35% reduction in interfacial charge-transfer resistance compared to unmodified glassy carbon electrodes. Voltammetric studies demonstrate that MTZ reduction at the Ni-rGO interface proceeds via a diffusion-dominated, proton-coupled electron transfer mechanism at physiological pH (7.4). Under optimal conditions, the sensor exhibits a wide linear range of 2-200 µM, a low detection limit of 122.6 nM, and a high sensitivity of 5111.9 µA mM⁻¹ cm⁻². The sensor exhibited high fabrication reproducibility (3.12% relative standard deviation across five independent electrodes), operational repeatability (95.4% signal retention over 10 continuous cycles), and storage stability (91.9% retention after 7 days). The analytical response remained unaffected by 10-fold excesses of common inorganic ions, endogenous biological species (dopamine, ascorbic acid, uric acid), and the structural analog imidazole, as well as 5-fold excesses of commonly used antibiotics, confirming the sensor's strict specificity toward the target analyte. Recovery rates of 87-108% across tap water and human urine matrices confirm the practical analytical utility of the Ni-rGO sensor for real-world MTZ monitoring in both environmental and clinical contexts.
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BibTeX
@article{mubin2026hierarchical,
title = {{Hierarchical Ni-rGO nanocomposite derived from e-waste graphite for trace-level electrochemical sensing of metronidazole.}},
author = {Abdullah Ibn Masud Mubin and Md Humayun Kabir and Md Qamrul Ehsan and Othai Saha and Sourav Datta and Md Sanwar Hossain and Md Yeasin Pabel and Muhammad Shahriar Bashar and Sabina Yasmin},
journal = {RSC advances},
year = {2026},
month = oct,
doi = {10.1039/d6ra06899e},
url = {https://europepmc.org/article/MED/42909315},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Hierarchical Ni-rGO nanocomposite derived from e-waste graphite for trace-level electrochemical sensing of metronidazole.
AU - Abdullah Ibn Masud Mubin
AU - Md Humayun Kabir
AU - Md Qamrul Ehsan
AU - Othai Saha
AU - Sourav Datta
AU - Md Sanwar Hossain
AU - Md Yeasin Pabel
AU - Muhammad Shahriar Bashar
AU - Sabina Yasmin
PY - 2026
DA - 2026/10/01
JO - RSC advances
DO - 10.1039/d6ra06899e
UR - https://europepmc.org/article/MED/42909315
AB - Metronidazole (MTZ) accumulation in aquatic systems presents severe environmental and public health risks, requiring sensitive trace-level monitoring techniques. Here, we report the development of an electrochemical sensor based on a reduced graphene oxide (rGO) nanocomposite decorated with nickel-containing nanophases (Ni-rGO). The graphene oxide support was synthesized from graphite sustainably recovered from discarded lithium-ion batteries prior to integration via a one-pot, hydrazine-free hydrothermal method. Morphological and structural analyses (SEM, TEM, XRD, FTIR) reveal a hierarchical architecture where highly dispersed, ultra-small (1.5-3 nm) nickel-containing domains coexist with larger crystalline domains anchored to a porous rGO network. This dual-scale structure likely prevents graphene restacking, resulting in a 41.2% increase in electrochemically active surface area and a 43.35% reduction in interfacial charge-transfer resistance compared to unmodified glassy carbon electrodes. Voltammetric studies demonstrate that MTZ reduction at the Ni-rGO interface proceeds via a diffusion-dominated, proton-coupled electron transfer mechanism at physiological pH (7.4). Under optimal conditions, the sensor exhibits a wide linear range of 2-200 µM, a low detection limit of 122.6 nM, and a high sensitivity of 5111.9 µA mM⁻¹ cm⁻². The sensor exhibited high fabrication reproducibility (3.12% relative standard deviation across five independent electrodes), operational repeatability (95.4% signal retention over 10 continuous cycles), and storage stability (91.9% retention after 7 days). The analytical response remained unaffected by 10-fold excesses of common inorganic ions, endogenous biological species (dopamine, ascorbic acid, uric acid), and the structural analog imidazole, as well as 5-fold excesses of commonly used antibiotics, confirming the sensor's strict specificity toward the target analyte. Recovery rates of 87-108% across tap water and human urine matrices confirm the practical analytical utility of the Ni-rGO sensor for real-world MTZ monitoring in both environmental and clinical contexts.
SN - 2046-2069
ER -