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<p>This research underscores the capabilities of modified pencil graphite electrodes (PGE) in the electrochemical detection of ascorbic acid. The innovative design of the PGE/chitosan/thiophanate-methyl sensor, combined with the advantages of cyclic voltammetry and square wave voltammetry, offers a promising approach for developing sensitive and selective electrochemical sensors. The surface nano-modification of PGE with chitosan and thiophanate-methyl was confirmed through scanning electron microscopy. The parameters related to electrocatalysis were determined to be: the electron transfer rate constant (log Ks&#xa0;=&#xa0;2.98), the charge transfer coefficient (<i>α</i>&#xa0;=&#xa0;0.87), and the surface concentration of electroactive species (Γ&#xa0;=&#xa0;1.13&#xa0;×&#xa0;10<sup>-7</sup> mmol/cm<sup>2</sup>). A linear correlation was identified for ascorbic acid concentrations between 40 and 380 nanomolars (nM), with a limit of detection established at 13.29 nM. The reproducibility of the modified PGE/chitosan/thiophanate-methyl assay, assessed at a concentration of 140&#xa0;nM ascorbic acid using five constructed electrodes, resulted in a relative standard deviation (RSD) of 4.85%. The repeatability of the developed sensor for measuring 140&#xa0;nM of ascorbic acid, determined through 12 measurements with a single constructed electrode, produced a relative standard deviation (RSD%) of 4.68% (146.57&#xa0;±&#xa0;6.87). The electrochemical sensor, in contrast to conventional techniques, allows for rapid analysis, reduced expenses, and supports on-site testing. These sensors are essential tools for the analysis of human blood serum and pharmaceutical samples, as they are not affected by significant side effect interference.</p> Graphical Abstract <p></p>

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A Newly Developed Modified Pencil Graphite Electrode; Structured as PGE/Chitosan/Thiophanate-methyl for Voltammetry Quantification of Ascorbic Acid in Human Blood Serum and Pharmaceutical Supplement samples

  • 期刊论文

  • 发表日期：

    2025年12月9日

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  • Mohaned Habeb Ahmed Al-Khudhur,
  • Arash Babakhanian

摘要

This research underscores the capabilities of modified pencil graphite electrodes (PGE) in the electrochemical detection of ascorbic acid. The innovative design of the PGE/chitosan/thiophanate-methyl sensor, combined with the advantages of cyclic voltammetry and square wave voltammetry, offers a promising approach for developing sensitive and selective electrochemical sensors. The surface nano-modification of PGE with chitosan and thiophanate-methyl was confirmed through scanning electron microscopy. The parameters related to electrocatalysis were determined to be: the electron transfer rate constant (log Ks = 2.98), the charge transfer coefficient (α = 0.87), and the surface concentration of electroactive species (Γ = 1.13 × 10-7 mmol/cm2). A linear correlation was identified for ascorbic acid concentrations between 40 and 380 nanomolars (nM), with a limit of detection established at 13.29 nM. The reproducibility of the modified PGE/chitosan/thiophanate-methyl assay, assessed at a concentration of 140 nM ascorbic acid using five constructed electrodes, resulted in a relative standard deviation (RSD) of 4.85%. The repeatability of the developed sensor for measuring 140 nM of ascorbic acid, determined through 12 measurements with a single constructed electrode, produced a relative standard deviation (RSD%) of 4.68% (146.57 ± 6.87). The electrochemical sensor, in contrast to conventional techniques, allows for rapid analysis, reduced expenses, and supports on-site testing. These sensors are essential tools for the analysis of human blood serum and pharmaceutical samples, as they are not affected by significant side effect interference.

Graphical Abstract