Dual-Emissive Fluorescent Sensor Based on Functionalized Quantum Dots for the Simultaneous Determination of Nitric Oxide and Hydrogen Sulfide

A simple, direct fluorescent sensor was developed to simultaneously determine nitric oxide and hydrogen sulfide based on 4-(((3-aminonaphthalen-2-yl)amino)methyl)benzoic acid (DAN-1)-functionalized CdTe/CdS/ZnS quantum dots (QDs@DAN-1). In this sensor, DAN-1 could specifically recognize nitric oxide and yield highly fluorescent naphtho triazole (DAN-1-T). Meanwhile, the fluorescence intensity of the QDs could be quenched by hydrogen sulfide. The QDs and DAN-1-T could be simultaneously excited at 365 nm, and their maximum emission wavelengths were 635 and 440 nm, respectively. Nitric oxide and hydrogen sulfide were simultaneously determined by monitoring two different fluorescence signals. The limits of determination for nitric oxide and hydrogen sulfide were 0.051 and 0.13 μM, respectively. The QDs@DAN-1 sensor was also applied to determine nitric oxide and hydrogen sulfide in human plasma. This sensor may provide a new strategy for investigating the relationship between nitric oxide and hydrogen sulfide and elucidating their roles in related physiological and pathophysiological processes at the same time.