Dual-probe-based fluorescent sensor ensemble for the pattern recognition of various flavonols and its application in tea identification

Flavonols are widely distributed in complex samples such as food matrices, and the coexistence of multiple structurally similar flavonols in such samples renders identifying them highly challenging, while also bringing difficulties to the detection of real samples. Herein, a novel dual-probe-based fluorescent sensor ensemble composed of dansyl derivative (DanBrIM) aggregates and pyrene derivative (PyTS) was constructed and explored for differentiation of flavonols. The powerful DanBrIM/PyTS ensemble exhibits turn-off responses to seven different flavonols, owing to the synergistic effect of the inner filter effect and photo-induced electron transfer. Fingerprint recognition patterns, radar plots, heat maps, linear discriminant analysis and partial least squares-discriminant analysis results illustrate that the present sensor can effectively discriminate different flavonols, flavonol isomers and unknown samples by collecting fluorescence signals at three typical wavelengths. Moreover, it can be employed to distinguish various tea samples, demonstrating promising practical applications.