Fluorescent sensor based on bismuth metal-organic frameworks (Bi-MOFs) mimic enzyme for H2O2 detection in real samples and distinction of phenylenediamine isomers

Abstract

Although peroxidase-like nano-enzymes have been widely utilized in biosensors, nano-enzyme based biosensors are seldom used for both quantitative analysis of H₂O₂ and differentiation of isomers of organic compounds simultaneously. In this study, a dual-functional mimetic enzyme-based fluorescent sensor was constructed using metal-organic frameworks (Bi-MOFs) with exceptional oxidase activity and fluorescence properties. This mimetic enzyme sensor facilitated quantitative analysis of H₂O₂ and accurate discrimination of phenylenediamine isomers. The sensor exhibited a wide linear range (0.5-400 μM) and low detection limit (0.16 μM) for the detection of H₂O₂. Moreover, the sensor can also be used for the discrimination of phenylenediamine isomers, in which the presence of o-phenylenediamine (OPD) leads to the appearance of a new fluorescence emission peak at 555 nm, while the presence of p-phenylenediamine (PPD) significantly quenched its fluorescence due to the internal filtration effect. The proposed strategy exhibited a commendable capability in distinguishing phenylenediamine isomers, thereby paving the way for novel applications of MOFs in the field of environmental science.

Keywords: Dual-functional fluorescent probe; Fluorescence test strip; H(2)O(2) detection; Mimetic enzyme; Phenylenediamine isomers.