Design Of Dual-excitation And Dual-emission Fluorescent Probe Using Carbon Dots And Its Application Reserach In Detecting In Hydrazine And Glutathione

Carbon dots?CDs?is a high quality luminescent material.Compared with semiconductor quantum dots and rare earth metal nanoparticles,it has many remarkable properties,such as good water solubility,low cytotoxicity and high biocompatibility.At the same time,CDs can also be used as a reliable fluorescent probe in chemical and biological fields.When the fluorescent probe is used for substance detection or fluorescence imaging test,only the excitation light of itself is needed.It can avoid the influence of other background light sources,so that the substance can be accurately detected.In this paper,the dual-excitation and dual-emission fluorescent probe CDs-COO-F was designed and synthesized based on the characteristics of the detected substance hydrazine?N₂H₄?and the optical properties of carbon dots to detect N₂H₄ in environmental water samples and living cells.At the same time,according to the characteristics of glutathione?GSH?,the detection of glutathione was realized by the design and synthesis of Np-SO₂-NCDs as a dual-emission and dual-emission fluorescence probe.And some methods are used to characterize the synthesized material.Meanwhile,the selectivity and anti-interference ability of fluorescent probe were studied,the corresponding linear relationship was obtained and the corresponding mechanism of two kinds of fluorescent probes for material detection were proposed.The specific research content can be divided into the following two parts:1.In the first part,a new dual-excited and dual-emission fluorescent probe?CDs-COO-F?for the specific detection of N₂H₄ was designed and synthesized through the esterification reaction of carbon dots?CDs?and fluorescein?F?,mainly using the property that N₂H₄ can destroy ester bonds.First,carbon dots with carboxyl groups on the surface were prepared by using citric acid as carbon source using melting method.The CDs were characterized by means of transmission electron microscopy?TEM?,X-ray diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?,fourier transform infrared spectroscopy?FT-IR?and ultraviolet-visible absorption spectroscopy?UV-vis?.On the other hand,the effects of hydrazine concentration and interfering substances on N₂H₄ detection were studied.The high sensitivity and selectivity of CDs-COO-F to N₂H₄ were confirmed.The linear response and detection limit of the fluorescence emission intensity of CDs-COO-F at462 nm and 515 nm with the concentration of N₂H₄ were obtained under the excitation of 370 nm and 480 nm wavelength lights,respectively.According to the experimental results,the detection mechanism of CDs-COO-F on N₂H₄ was derived.Cell imaging and cytotoxicity of CDs-COO-F were measured.Finally,N₂H₄ was successfully detected by CDs-COO-F in water samples and living cells.The experimental results show that the fluorescent probe CDs-COO-F can be used to detect N₂H₄ in aqueous solution and living cells.2.In the second part,a novel dual-excitation and dual-emission fluorescent probe Np-SO₂-NCDs for the specific detection of GSH was designed and synthesized by the hinsber reaction between nitrogen-doped carbon dots?NCDs?and naphthyl sulfonyl chloride?Np-SO₂CI?.The nitrogen-doped carbon dots with amino groups were prepared by hydrothermal method by using citric acid as carbon source and ethylenediamine as nitrogen source.And the preparaed NCDs were characterized by the TEM,XRD,XPS and FT-IR.In addition,the effects of GSH concentration and co-existing substances on its detection were studied.The linear equation and LODs of the fluorescence emission intensity of Np-SO₂-NCDs at 432 nm and 495 nm with GSH concentration were obtained under the excitation of 320 nm and 370 nm wavelengths lights,respectively.According to the experimental results,the detection mechanism of GSH by Np-SO₂-NCDs was deduced.The cytotoxicity and cell imaging experiments of Np-SO₂-NCDs were performed.The experimental results show that the fluorescent probe Np-SO₂-NCDs can be used to detect GSH in solution and living cells.