The Synthesis And Sensing Propetries Of The Nano Composite Optochemical Sensors For Fluoride Ions And Mercury Ions In Aqueous Solution

Photochemical sensors are widely used in various fields of environmentalmonitoring, life sciences, medicine and military. It can be divided into two types inaccordance with the output signal: the colorimetric chemical sensors ues theUV-visible of light as an output signal, and the fluorescent chemical sensors ues thefluorescence as the output signal. The former detects objects by observing the colorchange of the solution. This makes detection more intuitive, convenient andinexpensive. The latter detects objects by the change of fluorescence intensity,fluorescence lifetime and emission wavelength. It has a lot of advantages such asgood selectivity, low detection limits and high sensitivity. Both sensors haveadvantages and disadvantages. In order to make their respective strengths to maximizeperformance, this paper carried out the following two part work, and achieved certainresults:The first part, we successfully synthesized a novel colorimetric chemical sensor(CR1) using1-pyrene formaldehyde and2,4-dinitrophenylhydrazine as rawmaterials. The UV titration in DMSO showed that F-and AcO-can be efficiently andsensitively detected by CR1, and the detection accompanied by a significant change incolor vision. This achieved a convenient naked eye detection. The sense mechanismbased on the formation of a neutral hydrogen bonding sites between the subject andobject. At the same time, we using F-and AcO-carried out the UV titration indifferent ratio of solvent. Tests showed that, CR1can detecte F-selectively in85%DMSO/15%H2O solvent system. This may provide a cheap, convenient, selectively,naked eye possibility for the detection of F-in aqueous solution.The second part, we successfully synthesized and characterized a novelfluorescent chemosensor (Eu@SiO2) using the rare earth ion complexes Eu (TPA) andSiO2nanoparticles as raw materials. Experiments show that, the fluorescentchemosensor (Eu@SiO2) have the same appearance and good dispersion.And thefluorescence titration in aqueous solution showed that Hg2+can be detected byEu@SiO2selectively and sensitively. The lowest detection limit was0.8μM.Thestrong fluorescence generated by Eu@SiO2can be quenched efficiently by Hg2+. Andthis fluorescence quenching is a dynamic quenching caused by the effective collisionof Hg2+and fluorescent molecules Eu@SiO2. Eu@SiO2is soluble in water and non-toxic, so this provides a possibility for the detection of low concentrations ofHg2+in vivo.