Preparation Of Novel Nitrogen-doped Carbon Quantum Dots And Application For Fluorescence Probe And Electrochemical Sensor

N-doped carbon quantum dots were gradually applied to the detection of inorganic metal ions,small organic molecules and biomacromolecules for their good catalytic properties,high fluorescence quantum yield and good biocompatibility.Hence,it has great application potential in establishment of chemical biosensors using the novel nanomaterials.In this paper,a novel N-doped carbon quantum dots(the N-CDs)was developed which have high fluorescence quantum yield and electrocatalytic ability for the oxidation of phenolics.Based on the properties above,we established fluorescence probe for copper ions detection and electrochemical sensor for bisphenol A(BPA)detection using the N-CDs.Details are described as below:1.We designed and synthesized a novel N-doped carbon quantum dots(the N-CDs),using citrate as carbon source and acetyl imide(PEI)as a nitrogen source.The N-CDs were synthesized by one-step hydrothermal method at a low temperature.We used TEM,FT-IR,UV-vis,fluorescence and XPS to characterize the morphology,composition and surface groups of the N-CDs.The N-CDs has good water solubility,high fluorescence quantum dots yield(40.2%)and good biocompatibility with the emission wavelength at 441 nm.1.Since the mineral nitrogen amino on the surface of the N-CDs complexing with copper ions in the solution,the fluorescence of the N-CDs will be quenched.Based on the principles above we designed the nano-fluorescent probe for the detection of copper ions,with the detection limit of 2 nM.Morever,the N-CDs have good water solubility and biocompatibility.And we we applied the N-CDs to the real samples of copper ion detection and laser confocal fluorescence imaging in human lung epithelial cells,suggesting that the fluorescent probe has great potential in the field of clinical medical.2.We modified the N-CDs on the glassy carbon electrode(GCE)and we found that the N-CDs can catalyze the oxidation of bisphenol A(BPA),suggesting a novel method in BPA sensing.After the experimental condition optimized,a new BPA electrochemical sensor was established.By detecting the changes of current intensity in the electrocatalytic oxidation process of BPA,we achieved BPA quantitative detection.The electrochemical sensor has various advantages such as the preparation is simple and the response is sensitive,with the detection limit of 1.3 nM.