Selective detection of Ochratoxin B in food by fluorescent sensor based on 2-mercapto-5-benzimidazole carboxylic acid-capped CdSe quantum dots

Ochratoxin B (OTB) that widely presented in food has significant cytotoxicity even at low concentration levels. Herein, a novel fluorescent sensor based on the 2-mercapto-5-benzimidazole carboxylic acid (MBI)-capped CdSe quantum dots (QDs) was established for the selective detection of OTB in food. Specifically, the synergistic effect of electrostatic interaction and intermolecular hydrogen bonds between MBI and OTB provided a direct and sensitive fluorescence signal that enables efficient recognition of OTB from other mycotoxins, even OTA with similar structures. Excellent linear detection performance for OTB is exhibited with a range from 0.037 ng/mL to 48.01 ng/mL and a detection limit of 0.016 ng/mL. Furthermore, our developed method exhibits good anti-interference stability against contaminants such as mycotoxins, inorganic salts and amino acids. Most importantly, the sensor demonstrates high sensitivity in real food samples with the recovery ranges from 96.51% to 104.7%, with an RSD of less than 2.67%.