Dual-template molecularly imprinted double emission proportional fluorescence sensor based on CsPbBr3 and CsPb(Br/I)3 perovskite quantum dots for visual, selective and sensitive detection of methyl eugenol and aristolochic acid A

Phenolic acids with extensive pharmacological activity often coexist with harmful impurities in traditional Chinese medicine (TCM). Therefore, it is imperative to meticulously scrutinize the presence of harmful components while assessing the efficacy of TCM. Here, we present a dual-template molecularly imprinted double emission ratio fluorescence sensor to selectively and sensitively detect methyl eugenol (ME) and aristolochic acid A (AAs). The sensor consists of CsPbBr3 and CsPb(Br/I)3 perovskite quantum dots molecularly imprinted polymer with dual emission peaks at 515 nm and 650 nm. Surprisingly, ME can only quench the emission peak at 650 nm, while AAs can quench both the two emission peaks. When ME and AA coexist, their effect on the peak at 515 nm is similar to that of AAs, but the peak at 650 nm was quenched more. Therefore, it is possible to qualitatively identified whether the presence of ME, AAs or both of them based on the different colors of the sensors. In addition, the ratio of fluorescence intensity at 650 nm and 515 nm exhibits good linear relationships with both the concentrations of ME and AAs with the limit of detection of 8.3 nM for ME and 9.6 nM for AAs. Meanwhile, different concentrations of target molecules cause significant color changes, making it possible to visually semi-quantitatively detect AA, ME and both of them. Moreover, the quenching mechanisms induced by ME and AAs were also investigated. Finally, the sensors have been successfully used to the determination of ME and AAs in Asarum of TCM.