مشخصات پژوهش

Background: Förster resonance energy transfer (FRET) is a unique technique for probing subtle changes in molecular conformation, association, and separation between donor and acceptor. The intrinsic mechanism of FRET is that the donor fluorophore is excited by absorbing a photon, and then the energy is transferred to a nearby acceptor molecule through a non-radiation pathway [1, 2]. Carbon dots (CDs) have attracted more and more interests due to their excellent properties as small size (2–10 nm), nontoxicity, biocompatibility and feasible cell permeability, which have been extensively applied to analytical detection and imaging. In the present study, we have designed a FRET assembly among carbon dots (CDs) and silver (Ag) nano-particles (NPs) as perfect donor and acceptor, respectively and successfully applied as mercury sensor. Methods: The carbon dots were synthesized by a hydrothermal method. Citrate-stabilized Ag nanoparticles were synthesized and used as acceptor. Novel synthesized carbon dots were characterized by FT-IR, carbon NMR, hydrogen NMR, TEM and SEM. The spectral information demonstrate the well synthesized carbon dots with the size of less than 10 nm. UV-Vis spectra were also used to show the possibility of the FRET assembly between Ag NPs and carbon dots. Results: Due to FRET assembly between Ag NPs and carbon dots, the fluorescence emission intensity of carbon dots decreases by the addition of Ag NPs. The suggested system was applied for mercury determination. All related parameters which can affect the efficiency of the method were optimized. After the optimization, Hg determination was applied with the proper selectivity and accuracy in the concentration range of 0.25 ppb-0.25 ppm, with a detection limit of 0.07 ppb. Conclusion: A new carbon dot was applied for the construction of FRET assembly as donor. As a result, determination of mercury ions in real samples were carried out by the accurate, fast and inexpensive method which has been rarely a