Fluorinated ZnFe^III Hollow Metal-Organic Framework as a ¹⁹F NMR Probe for Highly Sensitive and Selective Detection of Hydrogen Sulfide.

ABSTRACT: Hydrogen sulfide (H₂S) is considered as a highly toxic environmental pollutant and an important signal transmitter in physiological processes, and the selective and reliable detection of H₂S is of great concern and remains challenging. Herein, we report a smart sensitive "off-on" ¹⁹F NMR sensor for H₂S by partially introducing a fluorinated ligand to construct a hollow dual metal-organic framework (MOF) nanosystem, F-ZnFe^III hMOF, in which the fluorinated ligand acts as the ¹⁹F signal source but is initially quenched due to the strong paramagnetic relaxation enhancement (PRE) effect from neighboring Fe³⁺ nodes. Upon exposure to sulfide ions, reduction of Fe³⁺ to Fe²⁺ is specifically triggered, which attenuates PRE efficiency, thus turning on the ¹⁹F NMR signal. The unique hollow MOF architecture benefits the mobility of ¹⁹F atoms, thereby improving the response sensitivity. Meanwhile, the desirable H₂S-sorption feature and appropriate redox potential of Fe³⁺/Fe²⁺ account for the favorable selectivity. The increase in the ¹⁹F signal is linear with the concentration of sulfide in the range of 20 to 150 ?M with a detection limit of 2.8 ?M. The probe is well demonstrated by analyzing H₂S in complex matrixes such as biological and foodstuff samples.

SUBMITTER: Hu G 

PROVIDER: S-EPMC7161043 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature