Hu Gaofei, Li Yina, Li Liangyu, Xu Suying, Wang Leyu
State Key Laboratory of Chemical Resource Engineering, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
ACS Omega. 2020 Mar 30;5(14):8373-8379. doi: 10.1021/acsomega.0c00893. eCollection 2020 Apr 14.
Hydrogen sulfide (HS) is considered as a highly toxic environmental pollutant and an important signal transmitter in physiological processes, and the selective and reliable detection of HS is of great concern and remains challenging. Herein, we report a smart sensitive "off-on" F NMR sensor for HS by partially introducing a fluorinated ligand to construct a hollow dual metal-organic framework (MOF) nanosystem, F-ZnFe hMOF, in which the fluorinated ligand acts as the F signal source but is initially quenched due to the strong paramagnetic relaxation enhancement (PRE) effect from neighboring Fe nodes. Upon exposure to sulfide ions, reduction of Fe to Fe is specifically triggered, which attenuates PRE efficiency, thus turning on the F NMR signal. The unique hollow MOF architecture benefits the mobility of F atoms, thereby improving the response sensitivity. Meanwhile, the desirable HS-sorption feature and appropriate redox potential of Fe/Fe account for the favorable selectivity. The increase in the F signal is linear with the concentration of sulfide in the range of 20 to 150 μM with a detection limit of 2.8 μM. The probe is well demonstrated by analyzing HS in complex matrixes such as biological and foodstuff samples.
硫化氢（HS）被认为是一种剧毒的环境污染物，同时也是生理过程中的重要信号传递分子，因此对HS进行选择性和可靠的检测备受关注且仍具挑战性。在此，我们报道了一种智能灵敏的“关-开”型氟核磁共振传感器用于检测HS，通过部分引入氟化配体构建了一种中空双金属有机框架（MOF）纳米体系，即F-ZnFe hMOF，其中氟化配体作为氟信号源，但由于邻近铁节点的强顺磁弛豫增强（PRE）效应，其信号最初被淬灭。当暴露于硫离子时，铁特异性地被还原为亚铁，这减弱了PRE效率，从而开启氟核磁共振信号。独特的中空MOF结构有利于氟原子的移动性，进而提高了响应灵敏度。同时，理想的HS吸附特性以及亚铁/铁合适的氧化还原电位解释了良好的选择性。氟信号的增加与20至150μM范围内的硫离子浓度呈线性关系，检测限为2.8μM。通过分析生物和食品等复杂基质中的HS，充分证明了该探针的性能。
