In Situ Specific Chromogenic and Fluorogenic Reaction for Straight forward and Dual-Modal Dopamine Detection

Dopamine is a crucial monoamine neurotransmitter involved in multiple cognitive functions and pathological processes. Herein, we described a rapid chromogenic and fluorogenic reaction between dopamine and naphthoresorcinol under ambient conditions, and found that the product possessed intense visible absorbance and high fluorescence quantum yield (78%) in aqueous solution. Through electrospray ionization-mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) analysis, the plausible reaction mechanism between dopamine and naphthoresorcinol was deduced, and the structure of the reaction product was confirmed. Inspired by the explicit mechanism and accessible reaction conditions, a straightforward and selective assay for dopamine concentration was developed with colorimetric and fluorescent dual-modal signals based on the in situ reaction.