Enhanced peroxidase-like activity of bimetal (Fe/Co) MIL-101 for determination of tetracycline and hydrogen peroxide

Abstract

An increase of the peroxidase-like activity of nanozymes is an important precondition for constructing real-time sensing platforms. In this work, the synthesized bimetal MIL-101(Fe/Co) nano-polyhedrons exhibit a much higher peroxidase-like activity than that of single-metal MOF MIL-101(Fe). Surprisingly, the peroxidase-like activity of MIL-101(Fe/Co) is enhanced in the presence of tetracycline. The catalytic performance of MIL-101(Fe/Co) nanozyme is investigated by virtue of the color change of a chromogenic substrate (TMB) together with the corresponding absorbance at 652 nm. Free radical scavengers and fluorescent probe verify that the enhanced peroxidase-like activity of MIL-101(Fe/Co) is ascribed to lots of hydroxyl radicals (˙OH) produced in the process of catalysis. Based on the superior peroxidase-like activity of MIL-101(Fe/Co), a fast economic colorimetric sensing platform for determination of tetracycline is established in the linear range of 1–8 μM with a detection limit of 0.24 μM. Furthermore, a dual-channel method (colorimetric and fluorometric) is designed to determine H₂O₂ in the wide range of 1–80 μM with a detection limit of 0.26 μM.