A colorimetric biosensor for simultaneous ochratoxin A and aflatoxins B1 detection in agricultural products

Colorimetric biosensors have been widely applied to mycotoxins testing. However, the colorimetric assay previously reported used a single color to detect one mycotoxin, and there were few reports on the simultaneous detection of multiple mycotoxins. In this work, a colorimetric biosensor for dual mycotoxins detection was developed. A Fe₃O₄/GO based platform for aflatoxins B1 (AFB1) detection and a Fe₃O₄@Au based platform for ochratoxin A (OTA) detection were fabricated. The quantification of OTA and AFB1 was respectively achieved by the release of thymolphthalein under alkaline conditions and 3,3',5,5'-tetramethylbenzidine was catalyzed by Au NPs under acidic conditions. Because of different conditions, two sensing methods didn't interfere with each other but could provide a higher detection efficiency. The detection range of AFB1 is 5-250 ng·ml^-1 and that of OTA is 0.5-80 ng·ml^-1. This biosensor has been successfully applied in real sample detection, which has a broad application prospect in fields of food safety.