{
  "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.",
  "abstract_shown": true,
  "affiliations": [
    "Institute of National Analytical Research and Service (INARS), Bangladesh Council of Scientific and Industrial Research (BCSIR) Dhanmondi Dhaka-1205 Bangladesh sabinayasmin@bcsir.gov.bd.",
    "Department of Chemistry, University of Dhaka Dhaka-1000 Bangladesh.",
    "Institute of Food Science and Technology (IFST), Bangladesh Council of Scientific and Industrial Research (BCSIR) Dhanmondi Dhaka-1205 Bangladesh humayunkabir@bcsir.gov.bd.",
    "Institute of Energy Research & Development (IERD), Bangladesh Council of Scientific and Industrial Research (BCSIR) Dhanmondi Dhaka-1205 Bangladesh."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 9,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Abdullah Ibn Masud Mubin",
      "orcid": "0009-0001-3774-9635"
    },
    {
      "affs": [
        2
      ],
      "name": "Md Humayun Kabir",
      "orcid": "0000-0002-1411-0943"
    },
    {
      "affs": [
        1
      ],
      "name": "Md Qamrul Ehsan",
      "orcid": "0000-0001-9925-1878"
    },
    {
      "affs": [
        0
      ],
      "name": "Othai Saha",
      "orcid": "0009-0002-6888-4271"
    },
    {
      "affs": [
        0
      ],
      "name": "Sourav Datta",
      "orcid": "0009-0007-3202-8728"
    },
    {
      "affs": [
        0
      ],
      "name": "Md Sanwar Hossain",
      "orcid": "0009-0006-6191-6022"
    },
    {
      "affs": [
        0
      ],
      "name": "Md Yeasin Pabel",
      "orcid": "0000-0001-9176-9242"
    },
    {
      "affs": [
        3
      ],
      "name": "Muhammad Shahriar Bashar"
    },
    {
      "affs": [
        0
      ],
      "name": "Sabina Yasmin",
      "orcid": "0000-0003-2279-1600"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/93qnqxtt0kxpk.bib",
  "cited_by": 0,
  "doi": "10.1039/d6ra06899e",
  "fulltext_url": "https://europepmc.org/articles/PMC13684875",
  "id": "93qnqxtt0kxpk",
  "issns": [
    "2046-2069"
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  "landing_url": "https://europepmc.org/article/MED/42909315",
  "language": "eng",
  "licence": "CC-BY-NC",
  "licence_label": "CC BY-NC",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "Chemistry"
    ],
    [
      "lcc",
      "QD1-999"
    ],
    [
      "openalex",
      "2208|Electrochemical sensors and biosensors"
    ]
  ],
  "openalex": "W7223091731",
  "pdf_url": "https://europepmc.org/articles/PMC13684875?pdf=render",
  "pmcid": "PMC13684875",
  "pmid": "42909315",
  "published": "2026-10-01",
  "publisher": "The Royal Society of Chemistry",
  "ris": "https://research.draconitic.com/paper/93qnqxtt0kxpk.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:20:10Z",
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  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "heading:Chemistry",
      "subfield": "general"
    }
  ],
  "title": "Hierarchical Ni-rGO nanocomposite derived from e-waste graphite for trace-level electrochemical sensing of metronidazole.",
  "title_text": "Hierarchical Ni-rGO nanocomposite derived from e-waste graphite for trace-level electrochemical sensing of metronidazole.",
  "type": "peer-reviewed",
  "updated_at": "2026-11-08T12:21:05Z",
  "url": "https://research.draconitic.com/paper/93qnqxtt0kxpk",
  "venue": "RSC advances",
  "versions": []
}