Preparation Of Carbon Dots From Corncob And Construction Of Carbon Dot-ionic Liquid-nanosilver Fluorescent Probe For The Detection Of Hydrogen Peroxide And Melamine

Carbon dots(CDs),also called carbon quantum dots,is a kind of zero-dimensional carbon nanomaterial with extremely small dimensions.Compared with traditional fluorescent nanomaterials such as Cd Te quantum dots,CDs has the characteristics of unique optical properties,wide selection of carbon sources,simple synthesis methods,easy surface modification,low cytotoxicity,and good biocompatibility.Therefore,since its discovery,CDs have received widespread attention.It is currently a hot issue to prepare CDs using biomass as a carbon source that is widely available in nature and available at a low price,and construct various fluorescent probes to achieve sensitive detection of certain substances.In this paper,using biological waste corncob as raw material,successfully prepared CDs with unique fluorescence characteristics,and cleverly constructed fluorescent probes that can be used for hydrogen peroxide and melamine detection.The specific work is as follows:1.Using corncob as carbon source,under the solubilizing effect of ionic liquid(IL),CDs@IL was successfully prepared by hydrothermal method.Transmission electron microscopy,X-ray powder diffraction,ultraviolet-visible diffuse reflectance absorption spectroscopy,fourier transform infrared spectroscopy,fluorescence spectroscopy,photoelectron spectroscopy and other methods were used to characterize the morphology,structural characteristics,and optical properties.The interaction between CDs@IL and common cations,anions,and amino acids was investigated.The stability and cytotoxicity of carbon dots under different p H,temperature,storage time and light time were also investigated.Finally,the cytotoxicity of carbon dots was evaluated.2.Using the effect of CDs@IL and silver nanoparticles(AgNPs),successfully prepared CDs@IL-AgNPs nano fluorescent probes,and further discussed the influence of hydrogen peroxide and melamine on the fluorescence emission of the probes,and established CDs@IL-AgNPs nano fluorescent probe to detect hydrogen peroxide and melamine,the detection mechanism of the probe was clarified.3.Investigating the effects of various interferences that may exist in the detection of melamine in dairy products by CDs@IL-AgNPs nano fluorescent probes,including various metal ions,vitamins,amino acids,food additives,food preservatives,etc.Finally,the fluorescent probe was successfully applied to the detection of actual samples,and the recovery rates of standard addition were 94%-110%.