Ratiometric fluorescence probes for visible detection and accurate identification of MPEA vapor

Methamphetamine (MA), as one kind of overflowed synthetic illicit drugs, has posed severe threats to health and social security. However, the on-site and visible fluorescence detection to MA remains limited. Herein, through covalently coupling diphenylacridine (DPA) and dimethylacridine (DMA) with pyridine, two ratiometric fluorescence probes (PyDPA and PyDMA) are constructed, which present rapid response, bathochromic-shifts over 100 nm and visible fluorescence color changes from blue to cyan upon the exposure to methylphenethylamine (MPEA, a simulant of MA). And the similar responses are observed for MA in confiscated samples. Further, a smartphone-based quantitative detected system is established to provide the on-site trace detection of MPEA as ppb level. Specially, PyDPA or PyDMA can identify MPEA from its interferences according to the unique ratiometric response based on their dual-emission-enhancement. Here, we show two ratiometric fluorescence probes to MA and MPEA with high potential for on-site application. This work introduces two novel fluorescent probes for methamphetamine detection. When exposed, they show a rare visible color shift and unique response pattern, enabling visual detection and accurate identification in complex environments