Morin-enabled ratiometric dopamine detection by forming azamonardine product

The important role to neuron communication and brain functions makes the selective and accurate detection of dopamine (DA, a typical neurotransmitter) significant. In this study, a morin-based probe has been reported for the ratiometric DA detection. The mechanism study discloses that the inside resorcinol motif can specifically react with DA and form fluorescent azamonardine-like product. In addition, the intrinsic emission from the internal chromophore endows ratiometric variation. With these features, selective DA sensing is realized using morin probe with a limit of detection of 2.2 nM (S/N = 3). Moreover, the practical application of the proposed method is further validated by the accurate DA determination in urine samples. This work demonstrates the possible exploration of novel small molecule-based ratiometric-sensing systems toward various analytes with the combination of proper reaction motif and chromophore. It is expected that the development of versatile probes for the ratiometric and accurate recognition of environmental and biological markers can refer such a design strategy.