Sensitive Ratiometric Detection of Vitamin B <sub>2</sub> by a Zn(II)-MOF with Tetranuclear Clusters
Xiaohong Wu, Yi-Ran Chi, Wenya Zhai, Zhong‐Lin Li, Fang-Hua Zhao
Abstract
High Resolution Image Download MS PowerPoint Slide Vitamin B 2 (VB 2 ) is an essential nutrient for the human body and plays important roles in human health. Therefore, the construction of an efficient sensor for VB 2 detection is required. Here, a fluorescent Zn(II)-MOF of 1,2-bis(benzimidazol-1-ylmethyl)benzene (1,2-bbix), {[Zn(1,2-bbix)(OH)](NO 3 )·0.5H 2 O} 2 n (MOF 1 ), was prepared for the ratiometric detection of VB 2 . MOF 1 displays an interesting 2-fold interpenetrated dia network based on tetranuclear Zn 4 clusters. MOF 1 emitted blue fluorescence at 409 nm, which was quenched after adding VB 2, while a new and enhanced emission at 537 nm associated with VB 2 was clearly observed, thereby establishing an effective ratiometric fluorescence method for VB 2 detection. MOF 1 can selectively detect VB 2 in aqueous media with the limit of detection being 0.11 μM. MOF 1 can also detect VB 2 in real food and pharmaceutical samples (milk and VB 2 tablets) with recoveries of 93.5–103.8%. The ratiometric sensing mechanism was investigated via powder X-ray diffraction (PXRD), IR, ultraviolet–visible (UV–vis), fluorescence lifetimes, X-ray photoelectron spectroscopy (XPS), and theoretical calculations. Additionally, a simple smartphone-assisted RGB method was developed for the visual detection of VB 2 . The present work provides an effective on–off ratiometric fluorescence sensor for VB 2 detection, which has great potential application in the food and pharmaceutical fields.