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<p>Quantum dot carbon (CQDs) is promising as a potential electrode modifier because the nanosized quantum dots with numerous electrocatalytic sites can bind tightly to the electrode without needing a binder. Humic acid extracted from natural peat has been employed to prepare CQDs using a facial hydrothermal procedure. The CQDs present spherical particles in the 3–10&#xa0;nm range with a high dispersion. The results showed that the CQDs have excitation-dependent fluorescence behavior. A CQDs-modified glassy carbon electrode (CQDs/GCE) was developed to enhance the electrochemical signals for 1,3-dimethylxanthine&#xa0;determination effectively. The 1,3-dimethylxanthine oxidation mechanism at the obtained electrode was investigated. The prepared CQDs/GCE exhibited excellent differential pulse voltammetry (DPV) responses toward the detection&#xa0;of 1,3-dimethylxanthine with a limit of detection of 0.93&#xa0;μM (<i>S</i>/<i>N</i> = 3) in the interval of 1.57–57.65&#xa0;μM. Real sample analysis has been successfully conducted in pharmaceutical formulations, which presented good recovery results of 98.3–103.7%. In ten successive measurements at 2.5–20&#xa0;μM, the relative standard deviation (RSD) was varied within 0.35–4.80%. Recording the electrochemical signals once a day using the same electrode for 7&#xa0;days offers only an RSD of 1.63%. For the seven CQDs/GCEs prepared using the same procedure, the RSD of the peak current was 0.66%. These results indicated that the proposed DPV method also revealed good reproducibility, repeatability, and long-term stability, making it a promising tool for practical application.</p>

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Electrochemical determination of 1,3-dimethylxanthine in pharmaceutical tablets using a peat-derived carbon quantum dots-modified glassy carbon electrode

  • 期刊论文

  • 发表日期：

    2025年3月9日

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  • Nguyen Phuoc Nhan,
  • Dang Thi Ngoc Hoa,
  • Le Van Thanh Son,
  • Nguyen Quang Man,
  • Nguyen Hai Phong,
  • Le Lam Son,
  • Ho Van Thanh,
  • Tran Thi Xuan Phuong,
  • Nguyen Trung Kien,
  • Nguyen Chi Bao,
  • Dao Ngoc Nhiem,
  • Dinh Quang Khieu

摘要

Quantum dot carbon (CQDs) is promising as a potential electrode modifier because the nanosized quantum dots with numerous electrocatalytic sites can bind tightly to the electrode without needing a binder. Humic acid extracted from natural peat has been employed to prepare CQDs using a facial hydrothermal procedure. The CQDs present spherical particles in the 3–10 nm range with a high dispersion. The results showed that the CQDs have excitation-dependent fluorescence behavior. A CQDs-modified glassy carbon electrode (CQDs/GCE) was developed to enhance the electrochemical signals for 1,3-dimethylxanthine determination effectively. The 1,3-dimethylxanthine oxidation mechanism at the obtained electrode was investigated. The prepared CQDs/GCE exhibited excellent differential pulse voltammetry (DPV) responses toward the detection of 1,3-dimethylxanthine with a limit of detection of 0.93 μM (S/N = 3) in the interval of 1.57–57.65 μM. Real sample analysis has been successfully conducted in pharmaceutical formulations, which presented good recovery results of 98.3–103.7%. In ten successive measurements at 2.5–20 μM, the relative standard deviation (RSD) was varied within 0.35–4.80%. Recording the electrochemical signals once a day using the same electrode for 7 days offers only an RSD of 1.63%. For the seven CQDs/GCEs prepared using the same procedure, the RSD of the peak current was 0.66%. These results indicated that the proposed DPV method also revealed good reproducibility, repeatability, and long-term stability, making it a promising tool for practical application.