Spectral Characteristics Of Luminescent Carbon Dots And Their Analytical Application As Fluorescent Probe

Photoluminescent carbon dots （CDs）, as a newly emergent fluorescence carbonnanomaterial, possess unique optical properties of high photostability against photobleaching,tunable excitation and emission wavelength, as well as low cytotoxicity and goodbiocompatibility. Therefore, they have become a hot subject of carbon nanomaterial. In thisdissertation, the CDs with excellent fluorescence properties have been synthesized withmircowave and the major research works are as follows:（1） The effects of different influencing factors including surfactants, oxidants, reducers,ions, pH, temperature and time on the fluorescence properties of CDs were investigated. Thevariations of the fluorescence signal and wavelength of CDs under the influence of the abovefactors were obtained. Results show that the fluorescence signal of CDs had excellentresponse to pH and some ions, which gave rise to the promising applications in pH sensor andion probe. These results laid the foundation for the deep study of the application of CDs.（2） A novel on-off fluorescent probe （Zr（CDs–COO）2EDTA） has been designed for fluorideions （F–） content detection based on the ligand competive reaction of the carboxylate groups（–COOH） on the surface of luminescent CDs coordinated to Zr（H2O）2EDTA and F–to formZr（F）₂EDTA complex. And the F in the on-off process was linear to the content of F–ranging from1.0×10^–10mol mL^–1to1.0×10^–8mol mL^–1. The probe has been applied to the F–detection in toothpaste and water sample with the satisfactory results, embodying its sensitive,accurate, selective, simple and pollution-free advantages. Moreover, the mechanism of theon-off probe for F–detection has also been discussed, which provided theoretical basis for theexploitation and application of novel on-off probe.（3） Based on the facts that lysine （Lys） could enhance the fluorescence intensity of bovineserum albumin modified-carbon dots （CDs–BSA） through decreasing the surface defects andthe fluorescence signal of the CDs–BSA–Lys system quenched in the presence of Cu²⁺, asensitive Lys enhancing CDs–BSA fluorescent probe has been designed for the detection ofCu²⁺(detection limit was5.8×10^–13mol mL^–1 for the first time. And this fluorescent probe has been utilized to detect Cu²⁺in hair and tap water samples with the results consisting withthose obtained by inductively coupled plasma mass spectroscopy, which indicated that thisproposed probe had analytical characteristics of good sensitivity, accuracy and selectivity. Themechanism of the proposed assay for the detection of Cu²⁺has also been discussed. Theresearch accelerated the methodology advance of the analytical application of CDs.