BACKGROUND: Aflatoxin B 1 (AFB 1 ) is the most toxic and harmful aflatoxin, and has good thermal stability. Research reveals that AFB 1 also exists in water, which is potentially harmful to human health. Therefore, it is urgent to remove AFB 1 from water. In this work, a novel magnetic covalent organic framework composite (Fe 3 O 4 @COFs) is synthesized. RESULTS:The specific surface area is as high as 1293.32 m 2 g −1 . The adsorption capacity for AFB 1 is 420 ∼g mg −1 , which is six times or more that of other adsorbents. Fe 3 O 4 @COFs is employed for the adsorption and elimination of AFB 1 from water. The removal efficiency is above 90% and it can be reused at least eight times. In addition, Fe 3 O 4 @COFs has been successfully used to remove trace AFB 1 in actual water samples.CONCLUSIONS: The synthesized Fe 3 O 4 @COFs has good thermal stability, fast adsorption and large adsorption capacity, and can be recycled many times. Fe 3 O 4 @COFs exhibits excellent performance for the removal of AFB 1 , and has exceptional promise for application in water purification.

We developed a new ochratoxin A (OTA) aptamer biosensor to promptly detect OTA in food. Mesoporous silica nanoparticles (MSN) were used as carriers, and aptamers were used as recognition probes and gating molecules. The fluorescent dye Rhodamine 6G (Rh6G) was loaded into mesoporous silica, and through electrostatic contact, the OTA aptamer was adsorbed on amino-modified mesoporous silica. The fluorescent dye released from the mesopore in the presence of OTA because of the conformational change induced in the aptamer by the target. The amount of ochratoxin was determined by measuring the fluorescence intensity. Our findings revealed a positive relationship between the fluorescence intensity and OTA concentration, with a limit of detection of 0.28 ng mL−1, and the detection range was 0.05–200 ng mL−1. The recovery rate was 80.7%–110.8% in real samples. The proposed approach is suitable for the quantification of other toxins.