Synthesis Of Novel Fluorescent Carbon Dots And Their Application In Detection

As a member of the carbon nano-family,the fluorescent carbon spot is an emerging carbon material less than 10 nm,which has important applications in ion detection and biomedicine.Compared with other nanoparticles,it has good water solubility,good biocompatibility,photobleaching resistance,excellent optical properties,chemical stability,stable optical properties,low cytotoxicity,a wide range of raw material sources and inexpensive,simple synthesis methods Variety,and environmental protection and many other advantages.Therefore,its preparation and application research has drawn extensive attention and has become one of the research hotspots in the field of luminescent nanomaterials.Although carbon dots have been widely reported in preparation methods and related applications,the most important drawback is the low fluorescence quantum yield.So finding a better method for preparing carbon dots and modifying carbon dots is crucial.In this paper,the surface of the exposed fluorescent carbon nanoparticles is first synthesized,then modified with hexamethylenediamine,and finally coated with amino acids.Then,the detection of two kinds of carbon dots and metal ions prepared by fluorescence spectroscopy was studied.The mechanism of fluorescence quenching or recovery was analyzed.The effect of metal ions on the fluorescence of carbon dots prepared was explored.The results of this study will provide reference for ion detection of carbon dots.The main research work in this article is summarized as follows:1.This article uses citric acid as a carbon source to synthesize surface-exposed fluorescent carbon nanoparticles in a polyethylene glycol aqueous solution by a hydrothermal/solvothermal synthesis method.At the same time,the surface exposed fluorescent carbon dots are prepared with hexamethylene diamine.After modification,lysine/glutathione is finally coated on the modified carbon spot to produce fluorescent carbon dots.The optimum synthesis conditions were determined by changing the amount of the reactants added,the temperature,and the time,so that the carbon spot fluorescence effect was the strongest.The morphologies and spectra of carbon dots were characterized by TEM,XRD,XPS,IR and fluorescence spectra.2.The first part of the experiment used fluorescence spectroscopy to explore the effect of Cr⁶⁺ions on the prepared carbon dots and showed a good linear relationship.After the toxicity test,the cell survival rate was higher than 80%.The results show that the fluorescent carbon dots prepared for the detection of Cr⁶⁺ions can be used in production.In the second part of the experiment,fluorescence spectroscopy was used to measure the quenching effect of Hg²⁺ions on the carbon dots coated with glutathione,followed by the use of penicillamine to restore the fluorescence.The recovered fluorescence spectra showed a good linear relationship and were tested for toxicity.The cell survival rate was higher than 80%.The results show that the prepared fluorescent carbon dots can be used to detect the content of penicillamine and can achieve the effect of removing Hg²⁺ions from the solution.The two carbon dots have excellent performance,good water solubility and biocompatibility,and photobleaching resistance.With the characteristics of good optical properties,stable chemical properties,stable optical properties,and low cytotoxicity,it is expected to be used as a new type of material in fields such as substance detection,biomarker,chemiluminescence,and bioimaging.