Metal–Organic Framework with Near-Infrared Luminescence for “Switch-on” Determination of Kaempferol and Quercetin by the Antenna Effect

Abstract

The establishment of a reliable and sensitive method for the detection of flavonoids, such as kaempferol (Kae) and quercetin (Que), is important and challenging in food chemistry and pharmacology because numerous structural analogues may interfere with the detection. Until now, designing an efficient switch-on fluorescence sensing strategy for Kae and Que was still in the unachievable stage. In this work, a switch-on near-infrared (NIR) luminescence sensing assay for Kae and Que was fabricated based on a metal−organic framework (MOF) called IQBA-Yb for the first time. The fluorescence enhancing mechanism was that analytes served as additional "antenna" of Yb 3+ , leading to the efficient switch-on NIR emission under excitation at 467 nm. Meanwhile, the combination results of experiment and theoretical calculation revealed that there existed hydrogen bonds between Kae, Que, and the MOF skeleton, further promoting the energy transfer between the analyte and Yb 3+ and facilitating fluorescence enhancement response. The developed probe possessed excellent sensing capability for Kae and Que, accompanied by a wide linear range (0.04−70, 0.06−90 μM), low detection limit (0.01, 0.06 μM), and short response time (20 min, 6 min), which was used to determine the Kae and Que contents in Green Lake and eatable Que samples with satisfactory results.

Metal–Organic Framework-Based Fluorescent Sensors for the Detection of Pharmaceutically Active Compounds

“…The PL turn-on of the Yb-MOF occurred after the addition of quercetin due to the electron transfer from quercetin to Yb 3+ via the antenna effect. 202 Wang et al developed two probes: carbon dot-embedded ZIF-8 MOF (CD@MOF) and carbon dot-embedded La-MOF in the molecular imprinted polymer (CD@MOF@MIP) for detecting quercetin. 203,204 The detection limits for quercetin by CD@ZIF-8-MOF and CD@La-MOF@MIP were 3.5 and 2.4 nM, respectively.…”

“…Cao et al designed a Yb-MOF to detect quercetin with a lower detection limit (0.06 μM) than that observed by Zhao et al The Yb-MOF could detect quercetin from lake water through a switch-on luminescence assay. The PL turn-on of the Yb-MOF occurred after the addition of quercetin due to the electron transfer from quercetin to Yb 3+ via the antenna effect . Wang et al developed two probes: carbon dot-embedded ZIF-8 MOF (CD@MOF) and carbon dot-embedded La-MOF in the molecular imprinted polymer (CD@MOF@MIP) for detecting quercetin. , The detection limits for quercetin by CD@ZIF-8-MOF and CD@La-MOF@MIP were 3.5 and 2.4 nM, respectively.…”

Novel Lanthanide-Based Metal–Organic Framework Isomer as a Double Ratiometric Fluorescent Probe for Vanillymandelic Acid

“…Metal–organic frameworks (MOFs), constructed by self-assemble of organic ligands and metal ions or metal nodes, − have drawn increased attention due to their potential applications in gas storage, molecular separations, and chemical sensing, as well as catalysis . Especially, MOFs have attracted great attention in the field of ratiometric fluorescence sensing. − Considering that the luminescence of MOFs could originate from ligands, metal ions, the charge interaction between ligands and metal ions, and guest molecules, the multiple emission centers of MOFs can be mainly obtained by introducing single or multiple lanthanide ions, , luminescent guest molecules, , carbon dots, Ru­(bpy) 3 2+ , and different organic linkers, along with lanthanide-based MOFs (Ln-MOFs) with single organic ligand and lanthanide ions. , Among them, most of the strategies generally require a complex post-synthetic modification process; thus, Ln-MOFs that are synthesized directly can be constructed as an ideal ratiometric fluorescence platform.…”