MOFs@POMs-derived bimetallic oxide Fe₂(MoO₄)₃ nanoparticles for sensitive colorimetric detection of salicylic acid in aspirin

A colorimetric sensing method for salicylic acid (SA) was developed by designing and fabricating bimetallic oxide nanozymes. Firstly, by calcinating MIL-100(Fe)@PMo₁₂ (MOFs@POMs) at different temperature, Fe₂(MoO₄)₃-Ts (T = 400℃, 500℃, 600℃, 700℃) nanoparticles (NPs) were successfully prepared. Secondly, by evaluating the peroxidase-like activities, Fe₂(MoO₄)₃–600 NPs shows the best peroxidase-like activity attributed to the Fenton-like effect and the synergistic coupling interaction between Mo and Fe. Finally, based on the specific complexation between SA and Fe³⁺, a sensitive colorimetric sensor for SA was established, which exhibits superior selectivity and interference with a detection limit of 0.11 μM and a linear range of 10 to 100 μM, the lowest LOD for SA to date, to the best of our knowledge.