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<p>Excessive consumption of synthetic food colourants such as tartrazine (TZ) poses significant health risks, highlighting the need for sensitive detection methods for food safety applications. Here, we report a binder-free electrochemical sensor based on synergistic integration of iron-based metal–organic framework MIL-100(Fe) with multiwalled carbon nanotubes (MWCNTs) on glassy carbon electrode (GCE). The nanocomposite leverages MIL-100's high porosity and accessible Fe<sup>3</sup>⁺ sites combined with MWCNT's superior conductivity, achieving an 11-fold enlarged electroactive surface area (0.786 cm<sup>2</sup>) and 19-fold enhanced exchange current density. Under optimized conditions using differential pulse voltammetry (DPV), the sensor exhibited a low detection limit (LOD) of 0.11&#xa0;μM, a wide linear range (0.9 to 7.5&#xa0;μM, R<sup>2</sup> = 0.9891), and excellent selectivity over amaranth (AM) and common interferents. Mechanistic studies revealed adsorption-controlled, one-electron/one-proton irreversible oxidation with ultralow charge transfer resistance (0.073 kΩ). The sensor demonstrated robust performance with excellent repeatability (RSD = 2.11%), reproducibility (RSD = 4.11%), and stability (&gt; 98% retention, 14&#xa0;days). Real-sample analysis of fruit juices and sweets yielded satisfactory recoveries (85.63–118.39%, RSD &lt; 2.17%) without pre-treatment. Monte Carlo (MC) simulations substantiated the selectivity mechanism, revealing stronger TZ adsorption sites relative to AM on the MIL-100(Fe)/MWCNTs nanocomposite. Density functional theory (DFT) calculations yielded valuable insights into the electronic properties and solvation behaviour of the isolated TZ, the MIL-100(Fe) fragment, and their composite (MIL-100(Fe)/TZ) system in aqueous environments. This integrated experimental-computational approach establishes a rational framework for developing next-generation MOF-based electrochemical sensors with predictable performance for food safety monitoring.</p>

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Electrochemical Detection of Tartrazine via MIL-100(Fe)/MWCNTs Nanocomposite: Integrated Experimental and Computational Insights

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年4月29日

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  • Thethiwe Promise Mthiyane,
  • Gloria Ebube Uwaya,
  • Suvardhan Kanchi,
  • Krishna Bisetty

摘要

Excessive consumption of synthetic food colourants such as tartrazine (TZ) poses significant health risks, highlighting the need for sensitive detection methods for food safety applications. Here, we report a binder-free electrochemical sensor based on synergistic integration of iron-based metal–organic framework MIL-100(Fe) with multiwalled carbon nanotubes (MWCNTs) on glassy carbon electrode (GCE). The nanocomposite leverages MIL-100's high porosity and accessible Fe3⁺ sites combined with MWCNT's superior conductivity, achieving an 11-fold enlarged electroactive surface area (0.786 cm2) and 19-fold enhanced exchange current density. Under optimized conditions using differential pulse voltammetry (DPV), the sensor exhibited a low detection limit (LOD) of 0.11 μM, a wide linear range (0.9 to 7.5 μM, R2 = 0.9891), and excellent selectivity over amaranth (AM) and common interferents. Mechanistic studies revealed adsorption-controlled, one-electron/one-proton irreversible oxidation with ultralow charge transfer resistance (0.073 kΩ). The sensor demonstrated robust performance with excellent repeatability (RSD = 2.11%), reproducibility (RSD = 4.11%), and stability (> 98% retention, 14 days). Real-sample analysis of fruit juices and sweets yielded satisfactory recoveries (85.63–118.39%, RSD < 2.17%) without pre-treatment. Monte Carlo (MC) simulations substantiated the selectivity mechanism, revealing stronger TZ adsorption sites relative to AM on the MIL-100(Fe)/MWCNTs nanocomposite. Density functional theory (DFT) calculations yielded valuable insights into the electronic properties and solvation behaviour of the isolated TZ, the MIL-100(Fe) fragment, and their composite (MIL-100(Fe)/TZ) system in aqueous environments. This integrated experimental-computational approach establishes a rational framework for developing next-generation MOF-based electrochemical sensors with predictable performance for food safety monitoring.