| Metal organic framework(MOF)is a new type of porous crystalline material formed by the coordination and assembly of metal nodes and organic ligands.Due to MOFs have simple synthesis conditions and diverse structures,it is widely used to construct fluorescent sensors.However,the single emission fluorescence sensor based on metal organic framework is susceptible to environmental interference,which will affect the detection accuracy.In recent years,through MOF pores or channels as hosts,and other luminescent guests(such as carbon dots(CDs)or dyes)as additional emission site is encapsulated in MOF,which formed the ratio fluorescence sensor with dual emission MOFs composites.Its not only possesses the capacity of self-reference for environment-free interferences but also realize the visual detection of color changes,improving sensitivity and selectivity.Therefore,based on the superiority of the MOFs composites ratio fluorescence sensor,this paper designs and synthesizes three dual-emission MOFs composites,which respectively realize the effective detection of Fe3+,PO43-and the anthrax biomarker DPA.Related research mainly includes the following three aspects:1.The ratio fluorescence sensor based on CDs/R6G@ZIF-8 composites is used to detect Fe3+.The blue luminescent carbon dots(CDs)and the green luminescent dye molecules of Rhodamine 6G(R6G)are encapsulated into the zeolite imidazole framework(ZIF-8)through the room temperature self-assembly reaction,we developed the ratio fluorescent probe CDs/R6G@ZIF-8,which can simple,rapid and sensitive detection of Fe3+.In this nanoprobe,the blue fluorescence of CDs at 438 nm is quenched by Fe3+ due to the internal filtering effect,while the green fluorescence of R6 G at 548 nm is not affected,which can be used as a reference signal.Therefore,it can realize the quantitative analysis of Fe3+ by changing the ratio of fluorescence intensity,and the probe can also be used for the detection of Fe3+ in actual samples.2.Detection of phosphate by dual emission fluorescent probe based on dye@Uio-66-NH2.This work has developed a new fluorescent sensing platform based on metal organic framework encapsulated dyes.The dye molecules of cresyl violet was encapsulated in the Uio-66-NH2 framework by solvothermal method,and the luminescent nanoprobe dye@Uio-66-NH2 composites with excellent luminescence performance and good water stability was prepared.The probe can generate dual emission at 435 nm and 625 nm at a single excitation wavelength of 348 nm.When PO43-is added,due to the higher affinity between PO43-and the Zr-O node in Uio-66-NH2,the charge transfer(LMCT)process of the ligand 2-aminoterephthalic acid to the metal is weakened,which promotes the fluorescence enhancement of the ligand.In addition,since the cresyl violet does not interact with PO43-,the fluorescence emission intensity of the material shows a trend of increased and unchanged.Therefore,it can be used as a ratio fluorescence sensor to realize the detection of PO43-in aqueous solution.3.R6G@Eu-MOF composites for sensitive ratiometric fluorescence detection of anthrax biomarker DPA.2,6-pyridinedicarboxylic acid(DPA),as a unique biomarker of bacillus anthracis,is highly toxic at trace levels and its pollution has shown great biological threat to homeland security.Here,we used a simple “in-situ one-pot” synthesis strategy to encapsulate the dye into the rare earth metal organic framework,and successfully prepared a dual-emission ratiometric fluorescent probe R6G@Eu-MOF,it achieves highly sensitive and selective detection of biomarkers DPA.Due to the Eu3+ has a strong coordination interaction with the carboxyl group in DPA,which can transfer energy from DPA to Eu3+,so that Eu-MOF sensitizes Eu3+ through the “antenna effect”,meanwhile,the red intrinsic fluorescence of Eu3+ is emitting.Therefore,it Can realize ratio detection DPA.In addition,the probe can also specifically identify DPA in human serum and water samples,which has important practical significance in actual analysis and monitoring. |
PDF Full Text Request