Casting red light for bad oil by dual turning-on mechanisms of fluorescence and its application in the portable platform

Cooking oil undergoes complicated reactions and generates harmful chemicals during the cooking process. Unfortunately, part of the bad cooking oil was illegally recycled and sold back to consumers. The conventional detection methods usually require heavy equipment and professional skills, which are not easily accessible to the public. Herein, we describe a robust turn-on fluorescent molecular probe, BOS (Bad Oil Sensor), for the straightforward and highly sensitive detection of bad cooking oil. BOS detects bad oil through the inevitable intrinsic change of viscosity and pH during cooking. Therefore, BOS enables the monitoring of cooking extent for any bad oil regardless of the origins, including adulterated oil. With the dual turn-on mechanisms and high sensitivity of BOS, a portable platform named Bad Oil Sensing System (BOSS) was constructed for the quick and simple in-field detection of bad oil. We believe that BOS and its portable platform will become a widely applicable tool for oil quality monitoring for the public and in the field of food chemistry.