Scholarlink

<p> A dual-mode sensor integrating colorimetric and fluorescent functionalities was constructed to enable sensitive, on-site visual detection of nitrite in food matrices, with CoFeMn hydroxide nanoflowers (CoFeMn HNFs) serving as a novel oxidase-mimicking nanozyme. First, the successful synthesis of CoFeMn HNFs was confirmed through a series of characterization techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Then, the synthesized CoFeMn HNFs, which exhibit remarkable oxidase-like activity, effectively catalyzed the oxidation of 3,3’,5,5’-tetramethylbenzidine (TMB) to its blue oxidized form (ox-TMB) via the generation of superoxide anion radicals (O<sub>2</sub><sup>•</sup>⁻). Its K<sub>m</sub> and V<sub>max</sub> values reached 0.399 mM and 2.8 × 10<sup>−7</sup> M·s<sup>−1</sup>, respectively, demonstrating not only significantly higher catalytic activity than horseradish peroxidase (HRP) but also efficient catalysis without the requirement of H<sub>2</sub>O<sub>2</sub>. In the presence of nitrite, ox-TMB undergoes a diazotization reaction to form yellow diazo products, accompanied by a distinct fluorescence quenching effect. In the colorimetric mode, the sensor exhibited an excellent linear response to nitrite over the concentration range 0.2 to 40&#xa0;µg/mL, accompanied by a limit of detection (LOD) as low as 0.063&#xa0;µg/mL. For the fluorescence mode, a superior linear range of 0.3 to 40&#xa0;µg/mL was achieved, with a LOD of&#xa0;0.223&#xa0;µg/mL nitrite. The results generated by this dual-mode sensor for real food samples were highly consistent with the reference values from the national standard method, thereby confirming its accuracy and practical utility. This work presents a versatile, reliable, and cost-effective nanozyme-based platform that addresses a critical need for sensitive, rapid, and on-site nitrite monitoring in food products, with broad implications for improving food safety surveillance and protecting public health.</p> Graphical Abstract <p></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Dual-mode colorimetric/fluorescence nitrite sensor enabled by CoFeMn hydroxide nanoflower nanozyme

  • 期刊论文

  • 发表日期：

    2026年2月26日

查看全文
  • Xiaoyue Yue,
  • Chenxu Hao,
  • Jinhua Ji,
  • Hui Zhang,
  • Yuewen Peng,
  • Yanhong Bai

摘要

A dual-mode sensor integrating colorimetric and fluorescent functionalities was constructed to enable sensitive, on-site visual detection of nitrite in food matrices, with CoFeMn hydroxide nanoflowers (CoFeMn HNFs) serving as a novel oxidase-mimicking nanozyme. First, the successful synthesis of CoFeMn HNFs was confirmed through a series of characterization techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Then, the synthesized CoFeMn HNFs, which exhibit remarkable oxidase-like activity, effectively catalyzed the oxidation of 3,3’,5,5’-tetramethylbenzidine (TMB) to its blue oxidized form (ox-TMB) via the generation of superoxide anion radicals (O2•⁻). Its Km and Vmax values reached 0.399 mM and 2.8 × 10−7 M·s−1, respectively, demonstrating not only significantly higher catalytic activity than horseradish peroxidase (HRP) but also efficient catalysis without the requirement of H2O2. In the presence of nitrite, ox-TMB undergoes a diazotization reaction to form yellow diazo products, accompanied by a distinct fluorescence quenching effect. In the colorimetric mode, the sensor exhibited an excellent linear response to nitrite over the concentration range 0.2 to 40 µg/mL, accompanied by a limit of detection (LOD) as low as 0.063 µg/mL. For the fluorescence mode, a superior linear range of 0.3 to 40 µg/mL was achieved, with a LOD of 0.223 µg/mL nitrite. The results generated by this dual-mode sensor for real food samples were highly consistent with the reference values from the national standard method, thereby confirming its accuracy and practical utility. This work presents a versatile, reliable, and cost-effective nanozyme-based platform that addresses a critical need for sensitive, rapid, and on-site nitrite monitoring in food products, with broad implications for improving food safety surveillance and protecting public health.

Graphical Abstract