Loading fluorescent dyes into MOF pores for the optical sensing and adsorption of heavy metal ions: synthesis, characterization, and performance

IF 4.3 2区化学 Q1 SPECTROSCOPY

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy Pub Date : 2025-05-01 DOI:10.1016/j.saa.2025.126323

Xiaoqiang Pu , Juan Zhao

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Abstract

The detection and removal of Cu(II) cations are an important topic in environmental protection and human health. Optical sensing platforms based on luminescent probes seem attractive due to their optical signal outputs which are free of electromagnetic interference, low cost, fast response, and high sensitivity. In this work, two azobenzene-based sensing probes (P1 and P2) were synthesized, and their sensing performance was firstly evaluated by their spectroscopic response towards various ions. P1 showed good sensing selectivity towards Cu²⁺ by forming an adduct with stoichiometric ratio of 1:1, as confirmed by Job’s plot, NMR, XPS, and EPR (electron paramagnetic resonance) comparison. P2 showed sensing behavior not only towards Cu²⁺ but also towards Fe²⁺, Fe³⁺, and Hg²⁺ due to the increased bonding affinity of –OH group. These two azobenzene-based probes were then covalently loaded into a MOF (metal–organic framework) matrix of bio-MOF-1 to endow it with optical sensing ability, as well as to improve the adsorption stability/capacity for metal cations. P_n@BMOF (n = 1, 2) samples were characterized by SEM, XRD, N₂ adsorption/desorption, IR, and elemental analysis. Their optical sensing and adsorption performance for metal cations were evaluated as well. Linear working equations were obtained with quenching constants and LOD values of 0.0884 μM⁻¹ and 0.22 μM for P1@BMOF, and 0.0998 μM⁻¹ and 0.20 μM for P2@BMOF. The adsorption levels for Cu²⁺ were determined as 0.97 mmol/g for P1@BMOF and 1.03 mmol/g for P2@BMOF.

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将荧光染料加载到MOF孔中用于重金属离子的光学传感和吸附：合成、表征和性能

Cu（II）阳离子的检测与去除是环境保护和人类健康的重要课题。基于发光探头的光传感平台因其光信号输出无电磁干扰、成本低、响应速度快、灵敏度高而备受关注。本文合成了两种偶氮苯基传感探针P1和P2，并首先通过它们对各种离子的光谱响应来评价它们的传感性能。通过Job’s plot、NMR、XPS和EPR（电子顺磁共振）比较，P1对Cu2+表现出良好的感应选择性，形成了化学计量比为1:1的加合物。P2不仅对Cu2+敏感，还对Fe2+、Fe3+、Hg2+敏感，这是由于-OH基团的亲和性增强所致。然后将这两种偶氮苯基探针以共价方式加载到生物MOF-1的金属有机框架（MOF）基质中，赋予其光学传感能力，并提高其对金属阳离子的吸附稳定性/容量。Pn@BMOF （n = 1,2）样品通过SEM、XRD、N2吸附/脱附、IR和元素分析进行了表征。并评价了它们对金属阳离子的光学传感和吸附性能。对于P1@BMOF和P2@BMOF，分别得到了淬火常数为0.0884 μM−1和0.22 μM、LOD值为0.0998 μM−1和0.20 μM的线性工作方程。对Cu2+的吸附水平P1@BMOF为0.97 mmol/g， P2@BMOF为1.03 mmol/g。

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来源期刊

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 物理-光谱学

CiteScore

8.40

自引率

11.40%

发文量

1364

审稿时长

40 days

期刊介绍： Spectrochimica Acta, Part A: Molecular and Biomolecular Spectroscopy (SAA) is an interdisciplinary journal which spans from basic to applied aspects of optical spectroscopy in chemistry, medicine, biology, and materials science. The journal publishes original scientific papers that feature high-quality spectroscopic data and analysis. From the broad range of optical spectroscopies, the emphasis is on electronic, vibrational or rotational spectra of molecules, rather than on spectroscopy based on magnetic moments. Criteria for publication in SAA are novelty, uniqueness, and outstanding quality. Routine applications of spectroscopic techniques and computational methods are not appropriate. Topics of particular interest of Spectrochimica Acta Part A include, but are not limited to: Spectroscopy and dynamics of bioanalytical, biomedical, environmental, and atmospheric sciences, Novel experimental techniques or instrumentation for molecular spectroscopy, Novel theoretical and computational methods, Novel applications in photochemistry and photobiology, Novel interpretational approaches as well as advances in data analysis based on electronic or vibrational spectroscopy.