Preparation And Analytical Application Of Fluorescent Probe Based On Graphene Quantum Dots Intercalated Hydrotalcite

Fluorescence spectrometry has the advantages of simple operation,short time consuming and so on,which is widely used in the qualitative and quantitative analysis of substances.The method is based on the relationship between the fluorescence signal of the fluorescence probe and the substance to be measured.As a new kind of carbon fluorescent material,graphene quantum dots have many advantages,such as convenient preparation,low cost,good water solubility and so on.At present,many researches use graphene quantum dots instead of traditional fluorescent dyes in the field of analysis and detection.In this paper,a fluorescent probe based on hydrotalcite confined graphene quantum dots was prepared and applied to analysis;the main contents are as follows:Firstly,citric acid was intercalated into the interlayer of hydrotalcite,and then the composite of graphene quantum dots and hydrotalcite was synthesized by hydrothermal method.Based on the quenching effect of Fe3+ on the composite,an "off-on" fluorescent probe was constructed for the detection of ascorbic acid and phytase.A series of characterization of the material was carried out.The properties of the fluorescent composite were analyzed.The detection conditions of the fluorescent probe and the quenching mechanism between the fluorescent probe and the substance were investigated.The linear range of ascorbic acid was 5-300 μmol L-1,and the detection limit was 1.73 μmol L-1;the linear range of phytase was 0.1-4 U mL-1,and the detection limit was 0.025 U mL-1.Finally,the fluorescent probe was applied to detect ascorbic acid in juice and phytase in feed.CdTe quantum dots have been synthesized by hydrothermal method with mercaptopropionic acid modification.Using CdTe quantum dots as fluorescence materials,composite of graphene quantum dots intercalated layered double hydroxides synthesized as reference fluorescence materials,a ratio fluorescence sensor for the detection of hydrogen peroxide and glucose was constructed.A series of characterization of the material was carried out,and the detection conditions and quenching mechanism between the fluorescent probe and the substance to be tested were investigated.The selectivity of the fluorescence sensor was studied,and a series of interfering substances in the sample system were studied.Finally,the ratio fluorescence sensor was applied to the determination of H2O2 in milk and glucose in human serum.The linear range of H2O2 was 10-300 μmol L"1,the detection limit was 2.6 μmol L-1;there was a good linear relationship between the fluorescence probe and the concentration of glucose in the range of 5-200 μmol L-1,the detection limit was 1.3 μmol L-1.Nitrogen doped graphene quantum dots intercalated layered double hydroxides were synthesized by hydrothermal method using citric acid as carbon source and urea as nitrogen source,and fluorescent probes were constructed based on the quenching effect of cytochrome c on the composites.A series of characterization of the material was carried out.The optimal conditions for the detection of cytochrome c were investigated,and the detection mechanism of the fluorescent sensor was analyzed.Finally,fluorescent probes were used to detect cytochrome c in human serum.The linear range and detection limit of cytochrome c were 3-400 μmol L-1 and 1.1 μmol L-1,respectively.