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<p>In this study, a novel non-enzymatic electrochemical sensor based on a nanocomposite of reduced graphene oxide and conducting polyaniline, denoted as reduced graphene oxide/polyaniline/glassy carbon electrode (rGO/PANI/GCE), was developed for detecting nitrate ions in environmental water sources. The reduced graphene oxide/polyaniline nanocomposite was synthesised by dispersing graphene oxide in water to form a homogeneous suspension, preparing polyaniline separately through chemical oxidative polymerisation, and subsequently combining them while reducing graphene oxide to reduced graphene oxide to produce a uniform composite material. The reduced graphene oxide/polyaniline nanocomposites were deposited on a glassy carbon electrode and applied as the working electrode. The nanocomposite was characterised using Fourier-transform infrared spectroscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. Cyclic voltammetry, electrochemical impedance spectroscopy, and square wave voltammetry were employed to evaluate the electrochemical behaviour of the sensor. The reduced graphene oxide/polyaniline/glassy carbon electrode exhibited electrocatalytic oxidation performance that surpassed those of the polyaniline/glassy carbon electrode, the graphene oxide/glassy carbon electrode, and the bare glassy carbon electrode. Under optimal conditions, the recorded current showed a linear correlation with nitrate ion concentration in the range of 7 to 45 µM. The regression equation was <i>I</i> = 22.943 + 0.863&#xa0;C (R<sup>2</sup> = 0.982). The sensor demonstrated a sensitivity of 0.863 µA µM<sup>−1</sup> with a detection limit of 1.74 µM. It also exhibited reproducibility with a relative standard deviation of 2.99% for nitrate ion detection. Recovery studies were conducted to assess the practical applicability of the sensor, yielding recovery rates between 95% and 105% for spiked samples. The sensor performed effectively with real water samples, demonstrating its suitability for reliable water quality monitoring.</p> Graphical abstract <p></p>

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Electrochemical nitrate sensing based on reduced graphene oxide/conducting polyaniline nanocomposite in environmental water sources

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年1月14日

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  • Siti Nur Akmar Mohd Yazid,
  • Mohamad Idris Saidin,
  • Illyas Md Isa,
  • Chin Suk Fun,
  • Ain Nadirah Romainor,
  • Nur Indah Wardani,
  • Mohamad Syahrizal Ahmad

摘要

In this study, a novel non-enzymatic electrochemical sensor based on a nanocomposite of reduced graphene oxide and conducting polyaniline, denoted as reduced graphene oxide/polyaniline/glassy carbon electrode (rGO/PANI/GCE), was developed for detecting nitrate ions in environmental water sources. The reduced graphene oxide/polyaniline nanocomposite was synthesised by dispersing graphene oxide in water to form a homogeneous suspension, preparing polyaniline separately through chemical oxidative polymerisation, and subsequently combining them while reducing graphene oxide to reduced graphene oxide to produce a uniform composite material. The reduced graphene oxide/polyaniline nanocomposites were deposited on a glassy carbon electrode and applied as the working electrode. The nanocomposite was characterised using Fourier-transform infrared spectroscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. Cyclic voltammetry, electrochemical impedance spectroscopy, and square wave voltammetry were employed to evaluate the electrochemical behaviour of the sensor. The reduced graphene oxide/polyaniline/glassy carbon electrode exhibited electrocatalytic oxidation performance that surpassed those of the polyaniline/glassy carbon electrode, the graphene oxide/glassy carbon electrode, and the bare glassy carbon electrode. Under optimal conditions, the recorded current showed a linear correlation with nitrate ion concentration in the range of 7 to 45 µM. The regression equation was I = 22.943 + 0.863 C (R2 = 0.982). The sensor demonstrated a sensitivity of 0.863 µA µM−1 with a detection limit of 1.74 µM. It also exhibited reproducibility with a relative standard deviation of 2.99% for nitrate ion detection. Recovery studies were conducted to assess the practical applicability of the sensor, yielding recovery rates between 95% and 105% for spiked samples. The sensor performed effectively with real water samples, demonstrating its suitability for reliable water quality monitoring.

Graphical abstract