Hydrothermal Synthesis of Carbon Dots from Luochuan Red Fuji Apple Peel and Application for the Detection of Fe3+ Ions

Carbon dots (CDs) synthesized from natural products received considerable attention due to their unique properties. In this work, CDs were synthesized using Luochuan Red Fuji apple peels as carbon source (Ap-CDs) by direct hydrothermal reaction, and were characterized by Transmission Electron Microscope (TEM), X-ray Diffraction (XRD), Raman spectra, Fourier-transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Ultraviolet and visible (UV-Vis) absorption spectra and Fluorescence (FL) spectroscopy. The effect of reaction temperature, reaction time and the amount of carbon source used on the fluorescent intensity of Ap-CDs was studied. Fluorescent properties measurement indicated that when irradiated by ultraviolet at the wavelength of 350[Formula: see text]nm, the Ap-CDs give out bright blue emitting at the maximum wavelength of 433[Formula: see text]nm with quantum yield of 9.43%. Meanwhile, it was found that the fluorescent intensity of Ap-CDs could be selectively quenched by Fe[Formula: see text] ions. The fluorescent quenching of Ap-CDs was linearly related to the concentration of Fe[Formula: see text] ion in the range of 0.05–300[Formula: see text][Formula: see text]M with the detection limit of 1.56[Formula: see text][Formula: see text]M. Accordingly, the concentration of Fe[Formula: see text] ion in the tap water and pork liver samples were tried to be measured by the fluorescent quenching Ap-CDs.