{
  "abstract": "RationaleUnderstanding speciation dynamics of trace metal elements (TMEs) is essential for assessing their environmental behavior and biological impacts. Time-integrated sensors represent one of the most effective approaches for detecting free metal ions and labile metal complexes in natural waters.\n\nMethodologyIn this work, mercury-free and cost-effective Gel-based Electrochemical sensor for the Measurement of Metal Availability (GEMMA) is here introduced. The device consists of a lab-made screen-printed electrode comprising the carbon counter electrode and the working electrode using Bismuth as the sensing element, overlaid with a diffusion-controlled agarose hydrogel layer. By leveraging the diffusion-driven transport of metal species, encompassing free ions and small complexes diffusion through the hydrogel and their accumulation at the electrode, GEMMA enables the quantification of free and labile metal concentrations in solution based on the amount collected over a defined deposition time. This study focuses on the preparation and optimization of a Bismuth-film electrode for the sensitive detection of Pb(II) at nanomolar levels using Stripping Chronopotentiometry (SCP).\n\nResultsKey aspects include electrochemical performance evaluation through Pb(II) calibrations and comparative analysis in the presence and absence of the hydrogel layer. Additionally, an exploratory speciation work examines Pb availability in the presence of a molecular ligand, offering insights into metal lability diagnosis and its implications for bioavailability in natural aquatic environments or laboratory-scale experiments.\n\nDiscussionThe GEMMA device demonstrates reliable Pb(II) speciation, though challenges like Bi surface oxidation at near-neutral pH and gel equilibration times remain. Future work will focus on refining electrode pre-treatments, exploring broader ligand Moussaoui EN26059 2 interactions, and coupling GEMMA with complementary techniques (e.g., AGNES for free metal quantification) to enhance accuracy in complex aquatic environments.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 5,
  "authors": [
    {
      "name": "Rima Moussaoui"
    },
    {
      "name": "Renaud Gley"
    },
    {
      "name": "Clément Bojic"
    },
    {
      "name": "José Paulo Pinheiro"
    },
    {
      "name": "Elise Rotureau"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/d73ksy26x4x64.bib",
  "cited_by": 0,
  "doi": null,
  "fulltext_url": null,
  "id": "d73ksy26x4x64",
  "issns": [
    "1448-2517",
    "1449-8979"
  ],
  "landing_url": "https://hal.univ-lorraine.fr/hal-05840893v1",
  "language": "en",
  "licence": "CC-BY-NC-SA-4.0",
  "licence_label": "CC BY-NC-SA 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-sa/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "hal",
      "0.chim"
    ],
    [
      "hal",
      "0.phys"
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      "1.chim.anal"
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  "openalex": null,
  "pdf_url": "https://hal.univ-lorraine.fr/hal-05840893/document",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-23",
  "publisher": "CSIRO Publishing",
  "ris": "https://research.draconitic.com/paper/d73ksy26x4x64.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:02Z",
      "native_id": "hal-05840893",
      "source": "hal",
      "url": "https://hal.univ-lorraine.fr/hal-05840893v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "hal:1.chim.anal",
      "subfield": "analytical"
    },
    {
      "field": "chemistry",
      "origin": "hal:2.phys.phys.phys-chem-ph",
      "subfield": "physical"
    },
    {
      "field": "earth",
      "origin": "hal:1.sdu.envi",
      "subfield": "environmental-science"
    },
    {
      "field": "physics",
      "origin": "hal:0.phys",
      "subfield": "general"
    }
  ],
  "title": "GEMMA: a Gel-based Electrochemical sensor for the Measurement of Metal Availability in solution",
  "title_text": "GEMMA: a Gel-based Electrochemical sensor for the Measurement of Metal Availability in solution",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:02Z",
  "url": "https://research.draconitic.com/paper/d73ksy26x4x64",
  "venue": "Environmental Chemistry",
  "versions": []
}