The efficient detection of highly toxic CrO42− and Hg2+ is of significant importance. Herein, a novel Eu-MOF with high quantum yield was synthesized via a one-step hydrothermal method. Through the strategic design and combination of ligands [2,2′-biquinoline]-4,4′-dicarboxylic acid (H2L) and 1,10-phenanthroline (Phen), the Eu-MOF exhibits excellent thermal stability, water stability, pH stability, photostability, and reproducibility. It also demonstrates outstanding sensing performance and anti-interference capability toward CrO42− and Hg2+. It has a Ksv of <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="604_2025_7344_Article_IEq1.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="73" /> </InlineMediaObject> <EquationSource Format="TEX">$1.73\times10^5$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>1.73</mn> <mo>×</mo> <msup> <mn>10</mn> <mn>5</mn> </msup> </mrow> </math></EquationSource> </InlineEquation> M−1 and a LOD of 3.78 nM for CrO42− detection, and a Ksv of <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="604_2025_7344_Article_IEq2.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="73" /> </InlineMediaObject> <EquationSource Format="TEX">$4.68\times10^5$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>4.68</mn> <mo>×</mo> <msup> <mn>10</mn> <mn>5</mn> </msup> </mrow> </math></EquationSource> </InlineEquation> M−1 and a LOD of 1.39 nM for Hg2+ detection, which may be attributed to its high quantum yield. The sensing mechanism for CrO42− involves fluorescence quenching due to competitive absorption of excitation energy between the Eu-MOF and CrO42−. In contrast, Hg2+ detection occurs via coordination of free nitrogen atoms sites in the Eu-MOF with Hg2+, forming a complex that quenches fluorescence. Test paper uniformly coated with the Eu-MOF was further developed. Finally, a portable fluorescence sensing platform integrating a smartphone and the Eu-MOF test paper was constructed, enabling convenient, rapid, and low-cost detection of CrO42− and Hg2+. This study provides a reference for preparing high quantum yield Eu-MOF and advancing portable sensing platforms. Graphical Abstract

A portable fluorescence sensing platform integrating smartphone and high quantum yield Eu-MOF probe for the detection of CrO₄²⁻ and Hg²⁺ in aqueous solutions

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发表日期：

2025年7月26日

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Deyan Liu,
Haining Dang,
Nanhai Zhang,
Qinghe Song,
Guangjun He,
Shixing Wang,
Libo Zhang

摘要

The efficient detection of highly toxic CrO₄²⁻ and Hg²⁺ is of significant importance. Herein, a novel Eu-MOF with high quantum yield was synthesized via a one-step hydrothermal method. Through the strategic design and combination of ligands [2,2′-biquinoline]-4,4′-dicarboxylic acid (H₂L) and 1,10-phenanthroline (Phen), the Eu-MOF exhibits excellent thermal stability, water stability, pH stability, photostability, and reproducibility. It also demonstrates outstanding sensing performance and anti-interference capability toward CrO₄²⁻ and Hg²⁺. It has a Ksv of $1.73\times10^5$ $1.73 \times 10^{5}$ M⁻¹ and a LOD of 3.78 nM for CrO₄²⁻ detection, and a Ksv of $4.68\times10^5$ $4.68 \times 10^{5}$ M⁻¹ and a LOD of 1.39 nM for Hg²⁺ detection, which may be attributed to its high quantum yield. The sensing mechanism for CrO₄²⁻ involves fluorescence quenching due to competitive absorption of excitation energy between the Eu-MOF and CrO₄²⁻. In contrast, Hg²⁺ detection occurs via coordination of free nitrogen atoms sites in the Eu-MOF with Hg²⁺, forming a complex that quenches fluorescence. Test paper uniformly coated with the Eu-MOF was further developed. Finally, a portable fluorescence sensing platform integrating a smartphone and the Eu-MOF test paper was constructed, enabling convenient, rapid, and low-cost detection of CrO₄²⁻ and Hg²⁺. This study provides a reference for preparing high quantum yield Eu-MOF and advancing portable sensing platforms.

Graphical Abstract

A portable fluorescence sensing platform integrating smartphone and high quantum yield Eu-MOF probe for the detection of CrO42− and Hg2+ in aqueous solutions

摘要

A portable fluorescence sensing platform integrating smartphone and high quantum yield Eu-MOF probe for the detection of CrO₄²⁻ and Hg²⁺ in aqueous solutions