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

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 mu M with a detection limit of 0.24 mu M. Furthermore, a dual-channel method (colorimetric and fluorometric) is designed to determine H2O2 in the wide range of 1-80 mu M with a detection limit of 0.26 mu M.

Automated summary

The bimetal MIL-101(Fe/Co) nano-polyhedrons synthesized in this work exhibit a much higher peroxidase-like activity than single-metal MOF MIL-101(Fe), and its activity is further enhanced in the presence of tetracycline. The catalytic performance of MIL-101(Fe/Co) nanozyme is studied by measuring the color change and absorbance of a chromogenic substrate, and it is found that the enhanced peroxidase-like activity is attributed to the production of hydroxyl radicals during catalysis. Based on the superior activity of MIL-101(Fe/Co), a fast and economical colorimetric sensing platform for detecting tetracycline, as well as a dual-channel method for detecting H2O2, are established.