A facile colorimetric sensor based on Fe₃O₄ magnetic nanoparticles with intrinsic catalytic activity for the rapid...

Ochratoxin A (OTA) is recognized as a Group 2B carcinogen and poses significant dangers to human, making it crucial to regulate OTA levels in food products. Herein, we developed a colorimetric approach to analyze OTA utilizing the intrinsic catalytic oxidized activity of Fe₃O₄ magnetic nanoparticles (MNPs). Our findings reveal that OTA shows a significant impact on the absorbance signal of the catalytic system, notably reducing the absorbance at 532 nm with H₂O₂ and 4-aminoantipyrene (4-AP). This sensor does not require elaborate aptamer or antibody, omitting the cumbersome reaction and the loss during synthesis, thus simply realizing OTA detection. The signal correlates linearly with the OTA concentrations and achieves satisfied sensitivity. The practical application has been verified utilizing beer and rice samples, resulting in recoveries ranging from 91.0 % to 106.2 %. This accuracy and reliability verified the method feasibility for monitoring OTA levels in food products.