Rational Design of ESIPT‐Based Ratiometric Fluorescent Probe for Rapid Detection of Dopamine in Banana Peel, Human Blood Serum, and Urine Samples

Abstract With dopamine's ( DA ) crucial role in managing mental health, developing an innovative, simple, and highly effective method for DA detection is beneficial for assessing neurological disorders. Herein, we reported a small molecule, ratiometric, excited state intramolecular proton transfer (ESIPT)‐based fluorescence probe ( DHB ) for ultrasensitive detection of dopamine. ESI‐MS, 1 H‐NMR spectra, and DFT study supported the detection mechanism. The product ( DHBD ) was highly stable in an excited state (2.54 ns). Encouraged by its rapid ratiometric response (< 1 min), low detection limit (65 nM), and good selectivity, it has been successfully employed for the real‐time quantification of dopamine in practical samples, including banana peel, human blood serum, and urine.