A simple "turn off-on" ratio fluorescent probe for sensitive detection of dopamine and lysine/arginine.

Abstract Herein, a novel and unique “off-on” single-excited dual-emissive ratio fluorescence sensor for highly selective and sensitive detection of dopamine and lysine/arginine has been developed via covalently connecting the yellowish-green fluorescent carbon dots (CDs) with the orange-red fluorescent AgInSe2@ZnS quantum dots (AISe QDs). This ratiometric fluorescence sensor provided with two-emission peaks at 495 and 575 nm under a single-excitation wavelength of 395 nm. The fluorescence of AISe QDs (F575) is effective quenched by dopamine and only efficientlyrecovered by lysine/arginine; meanwhile, the light of CDs (F495) remains unchanged. The fluorescence intensity ratio (F495/F575) showed a linear relationship with the concentration of DA in the range of 0-100 μM, and the detection limit as low as 0.21 nM. lysine and arginine with the detection limit of 0.36 nM and 26 μM, respectively. Furthermore, the fluorescence probe is successfully used to detect DA in human serum. Therefore, the as-synthesized probe shows excellent potential application for the determination of DA in real samples.