A layered Y(III)-viologen framework for efficient detection of nitrofurazone

Abstract

Two-dimensional (2D) materials as sensors show the unique advantage in detection because of the functional sites on their surface are easier to contact with analytes. Based on the Hard-Soft-Acid-Base theory, a nitrogen-rich metal–organic framework, [Y3(ipbp)4(HCOO)4(H2O)2]·NO3∙8.5H2O (Y-MOF) was synthesized by solvothermal reactions of a viologen ligand bromide 1-(3,5-isophthalic acid)-4,4′-bipyridine (H2ipbpBr) and Y3+ ions. It shows a 2D layered structure in which these uncoordinated pyridine groups of ipbp− hang on both sides of the layer as Lewis basic sites and exhibits excellent chemical stability in aqueous solutions within a pH range from 1 to 13. Fluorescent experiment indicates that Y-MOF possesses a high sensitivity for nitrofurazone (NFZ) with a low detection limit of 0.77 ​μg/mL and a high quenching constant of 1.36 ​× ​104 ​M−1. The cycling tests confirm that this MOF can be easily recovered and repeatedly used without an obvious performance loss. Furthermore, Y-MOF can detect NFZ in irrigation water, river water, and milk, in which satisfactory recoveries ranged from 94.70% to 109.85% with low Removable Storage Device (RSD) of 0.55%–2.76%. These results demonstrate that Y-MOF can be used as a potential sensor for the practical detection of NFZ in water environment and food matrix.