Homogeneous electrochemical and colorimetric dual-model analysis of tetracycline based on target-stimulated peroxidase like activity of MIL(Fe3Ni)-88B

Tetracycline (TC) is an effective antibiotic that is extensively used. However, incomplete use of TC would leave residues in various environmental substrates, and excessive accumulation of TC can cause permanent damage to organisms and human health. Consequently, it is crucial to develop a fast and simple TC detection technique. In this work, a hydrothermal approach was used to create an amino functionalized bimetallic organic framework of iron and nickel (MIL(Fe 3 Ni)-88B) for homogeneous electrochemical (HEC) and colorimetric detection of TC. The synergistic effects of Ni and Fe enhance the redox capacity of MIL(Fe 3 Ni)-88B, and the amino group on its surface can bind with TC through a hydrogen-bonding interaction, which causes the electronic interactions and further enhance the peroxidase-like (POD-like) activity of MIL(Fe 3 Ni)-88B. Thus, with H 2 O 2 and o-phenylenediamine (OPD) as reaction substrate, the Fenton reaction is enhanced by the transfer of the electron between TC and MIL(Fe 3 Ni)-88B, enabling HEC detection of TC. Meanwhile, OPD could be oxidized to yellow 2,3-diaminophenylazine (DAP) under the catalysis reaction, providing feasibility for colorimetric detection of TC. The constructed dual-model analysis of TC achieves a wide linear range of 0.01 ∼ 10.0 μM for HEC detection and 0.25 ∼ 25.0 μM for colorimetric method, respectively, coupled with the low detection limits of 0.003 and 0.086 μM. Additionally, due to the unique structure of MIL(Fe 3 Ni)-88B, it can be used for highly effective detection of TC in water samples, and the detection of TC in real water samples based on the dual-model strategy has high recoveries between 97.04 % and 103.76 %.