HPO42−-Enhanced Fluorescence of Ochratoxin A for Ultrasensitive Sensing

Ochratoxin A (OTA) is very difficult to detect by conventional fluorescent technique directly due to its natural fluorescence is very weak. For the first time, it was found that in the presence of HPO 4 2− , the fluorescence intensity of OTA could be dramatically enhanced by more than 30-fold within the range of 0.025–0.45 µM. Based on this unique ability of HPO 4 2− , a novel fluorescent sensing platform for OTA was developed, which exhibited good sensitivity and high selectivity. The detection range for OTA was from 0.025 to 0.45 µM with a detection limit of 7.3 nM. The proposed method is direct, simple, rapid, sensitive, selective, and does not require any sophisticated procedures. Furthermore, this strategy can be extended to the fluorescent colorimetric detection of OTA. This study successfully established a robust, user-friendly analytical method, effectively addressing a key limitation in the direct fluorescent detection of OTA.