A Novel Nitrogen-Doped Dual-Emission Carbon Dots as an Effective Fluorescent Probe for Ratiometric Detection Dopamine

Fluorescent carbon dots (CDs) as a new-type kind of zero-venami material have attracted growing interest. Herein, we developed a novel and convenient method to prepare dual emission nitrogen-doped carbon dots (N-CDs). Under ultraviolet (UV) light, N-CDs show blue and orange fluorescence centered at 435nm and 595nm, respectively. Because the two emission peaks of N-CDs exhibit different sensitivity to dopamine (DA), the N-CDs can serve as ratiometric fluorescent probes for DA measurement. The ratio ($I_{595\text{nm}}$/$I_{435\text{nm}}$) exhibits good linear relationship with DA concentration within the scope of 45–80$\mu$M. The quenching mechanism of N-CDs toward DA is also proposed, and it is suggested that the quenching may start because by the electrostatic interaction between N-CDs and DA.