High-performance fluorescent sensor based on CsPbBr3 quantum dots for rapid analysis of total polar materials in edible oils

Total polar materials (TPM) in edible oils are considered as the most reliable indicator for the quality of oil. However, the lack of suitable methods for TPM analysis has been an issue in the field of food safety. As is well known, all-inorganic perovskite quantum dots (QDs) are promising candidates for optoelectronic applications but severely restricted by their poor stability affected by environmental factors especially materials with high polarities. On the contrary, this instability to the change of polarity makes perovskite quantum dots particularly suitable as polarity sensors. In this work, CsPbBr3 QDs were synthesized and used to sense various solvents with different polarities. Good linear relationships between fluorescence intensity of CsPbBr3 QDs and volume of polar solvents, such as acetone, methanol, and ethanol, were achieved, separately, proving the feasibility of perovskite quantum dots as TPM sensor. The CsPbBr3 QDs were then used for the TPM detection in edible oils. With the increase of the TPM content, the fluorescence intensity of the CsPbBr3 QDs decreased proportionally without any PL peak shifts. The quenching effect was observed for olive oil, soybean oil, and sunflower oil, and the linear relationships were obtained in the TPM range of 17 %–31.5 %, 25 %–31.5 %, and 21.5 %–33 %, respectively. Moreover, a paper-based CsPbBr3 QDs fluorescent sensor was constructed for real-time monitoring of TPM content and exploring the possibility of a more rapid detection method as well. All the results indicate that CsPbBr3 QDs can be used as an innovative fluorescent sensor for rapid TPM detection of edible oils with great practical applications.