Green Synthesis of Fluorescent Carbon Nanodots from Chinese Wolfberry for Selective and Sensitive Detection of Ferric Iron

Water dispersible fluorescent carbon nanodots (CDs) were prepared by a facile and eco-friendly hydrothermal process using Chinese wolfberry as precursor without any further surface modification. The resolution transmission electron microscopy, Fourier transform infrared and X-ray photoelectron spectroscopy. It showed emission spectrum of blue which located at 400 nm with excited wavelength of 320 nm. High quantum yield of 54%, long lifetime of 9.04 mu s, and good biocompatibility were also observed. Importantly, the fluorescence intensity of CDs was selectively quenched within 2 min after addition of Fe3+. Based upon the phenomenon, a new fluorescent biosensor for detection of Fe3+ was proposed. No significant interference from other metal ions was observed. The linear range and detection limit for Fe3+ was 1-50 mu mol/L and 232 nmol/L (3 sigma), respectively. These superior properties demonstrated that the synthesized CDs had promising applications in the fields of environmental and biomedical science.