Ratio fluorescence test strip visualized by amino-functionalized metal–organic framework for rapid sensing of glyphosate

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2023-09, Vol.297, p.122673, Article 122673
• Main Authors: Wan, Chao-Qun, Pang, Yue-Hong, Zhai, Yong-Shun, Shen, Xiao-Fang
• Format: Article
• Language: English
• Subjects: Amino-functionalized metal–organic framework; Copper ion; Glyphosate; Ratio fluorescence test strip; Sensing
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2023.122673

[Display omitted] •A rapid fluorescence sensor based on amino-functionalized bismuth-based MOF and bonded with copper ion was constructed.•A ratio fluorescence test strip with separated sample area and calibration area was developed.•The fluorescent ring sticker as the binding-in self-calibration reduced errors from the angle and light dependency.•The portable device provided a reliable platform for on-site detection. As glyphosate is a broad-spectrum herbicide extensively used in agriculture worldwide, rapid glyphosate detection is essential for food safety and human health. Herein, a ratio fluorescence test strip was prepared and coupled with an amino-functionalized bismuth-based metal–organic framework (NH2-Bi-MOF) that bonded with copper ion for rapid visualization and determination of glyphosate. NH2-Bi-MOF had excellent fluorescence performance, and the copper ion, a Lewis acid, was selected as the quencher. The strong chelation of glyphosate with copper ion and its quick interaction with NH2-Bi-MOF would turn on the fluorescence signal, thus enabling the quantitative sensing of glyphosate, with a linear range of 0.10–200 µmol L−1, and recoveries between 94.8% and 113.5%. The system was then expanded to a ratio fluorescence test strip, in which the fluorescent ring sticker was set as a binding-in self-calibration to reduce errors from the angle and light dependency. The method realized the visual semi-quantitation referring to a standard card, as well as the ratio quantitation using the gray value output with LOD of 0.82 µmol L−1. And the as-developed test strip was accessible, portable, and reliable, thus offering a platform for the rapid on-site detection of glyphosate and other residual pesticides.