| Various ions and small molecules are closely related with the healthy of organisms and human,and slight changes of their contents may have important effects on the organism and human bodies.Therefore,the development of simple and effective method for detecting ions and small molecules is a key research direction in the field of analytical chemistry.Fluorescence probe technology has become an effective tool of analysis and detection due to its simple pre-processing,easy operation,high sensitivity,good selectivity,and low cost.In this thesis,three small-molecule fluorescent probes(A,B and C)were synthesized based on the fluorophore of 8-formyl-7-hydroxy-4-methylcoumarin to respectively rapid identify aluminum ions(Al3+),hydrated hydrazine(N2H4·H2O)and hypochlorite ion(Cl O-)in organisms.Their spectral characteristics,recognition mechanisms and application performances were detailedly studied.Probe A was synthesized by the condensation reaction of the coumarin fluorophore with furan-2-carbohydrazide.It exhibited obvious aggregation-induced emission(AIE)characteristic and excellent recognition ability to aluminum ions(Al3+),the detection limit(LOD)was as low as 1.4×10-8M.The probe showed weak fluorescence in benign solvent dimethyl formamide,while it showed obvious green fluorescence after adding a certain amount of water,which indicated that the probe aggregated in water to emit light.In addition,when Al3+and other interfering ions were added to the solution of probe A,it showed strong blue fluorescence.It has been proved that this probe is a turn on fluorescent probe with strong anti-interference,short response time,high selectivity and sensitivity,and can be used for detecting Al3+in water samples and fluorescence imaging of living cells.Fluorescent probe B for hydrated hydrazine(N2H4)was prepared by the reaction between coumarin fluorophore and 2-dicyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran.When the probe reacted with N2H4in aqueous solution,it has theremarkable characteristics including color change,fluorescence enhancement and wide p H range.The detection limits of ultraviolet analysis and fluorescence analysis were 5.59×10-6M and 8.18×10-8M,respectively.Because of its high sensitivity,strong anti-interference ability and fast response time,the probe has been successfully applied to the determination of N2H4 in water and the imaging of N2H4in living cells.A turn on fluorescent probe C was prepared by condensation reaction of coumarin and barbituric acid ester.Probe C could specifically recognize hypochlorite ion(Cl O-),and the detection limit was as low as 7.3×10-9M.After adding Cl O-,the fluorescence intensity of probe C increased significantly with the change of solution color.The probe could quickly monitor Cl O-within 5 min,and remain stable in a wide p H range(p H 3-11).In addition,the probe could perform dual-channel fluorescence imaging of Cl O-in living cells,and could be made into test paper to detect Cl O-in aqueous solution conveniently,quickly and intuitively. |
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