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

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, ¹H-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.