Fast, portable, selective, and ratiometric determination of ochratoxin A (OTA) by a fluorescent supramolecular sensor

Ochratoxin A (OTA), a mycotoxin found in various food items, possesses significant health risks due to its carcinogenic and toxic properties. Thus, detecting OTA is crucial to ensure food safety. Among the reported analytical methods, there has yet to be one that achieves fast, selective, and portable detection of OTA. In this study, we explore a novel supramolecular sensor, DOCE@ALB, utilizing human serum albumin as the host and a flavonoid fluorescent indicator as the guest. On the basis of indicator displacement assay, this sensor boasts an ultra-fast response time of just 5 s, high sensitivity with a limit of detection at 0.39 ppb, exceptional selectivity, and a noticeable ratiometric fluorescence response to OTA. This discernible color change and portability of the sensor make it suitable for on-site OTA detection in real food samples, including flour, beer, and wine, simply using a smartphone. In comparison to previously reported methods, our approach has showcased notable advantages in both response time and portability, addressing a critical need for food safety and regulatory compliance.