The Building And Application Of The System Based On Fluorescence Resonance Energy Transfer Between Quantum Dots And Porphyrin

Fluorescence resonance energy transfer techniques have been widely used in recent years,in order to satisfy more and more the application,the appearance of many new forms.In this paper,CdTe quantum dots and GQDs as donors,porphyrin with different functional groups into energy receptors,constructed different fluorescence resonance energy transfer system,the energy transfer system provides our country in analytical chemistry a new technical support rapid detection field which can be used as fluorescent probes used to the food safety testing,drug testing and detection of heavy metals,and other fields.The main research contents of this paper were as follow:1.Nanoparticles,semiconductor nanoparticles(semiconductor nanoparticles mainly include cadmium telluride quantum dots and graphene quantum dots),the properties and application of porphyrinswere and the mechanism and categories of FRET were reviewed.2.A sensitive and selective quantum dots(QDs)-5,10,15,20-tetra(4-pyridyl)po-rphyrin(TPyP)based fluorescence resonance energy transfer(FRET)biosensor was successfully fabricated for the detection of organophosphorus pesticides(OPs).Under the optimal conditions,a linear correlation was established between fluorescence intensity ratio ITPyp/IQDs and the concentration of paraoxon in the range of 9.09×10-12-1.09×10-6 mol L-1 with a detection limit of 3.15x 10'12 mol L-1.The proposed method was also applied to determine paraoxon in apples samples with recoveries ranging from 101.3%-102.7%and relative standard deviation(RSD)ranging from 0.9%-1.9%in all cases(n=3).Therefore,the proposed method was successfully applied to the determination of the OPs in real fruit samples with satisfactory results.3.Graphite power was used to synthesize graphene oxide using a modified Hummer method.The morphology structure of graphene oxide was characterized by scanning electron microscope,ultraviolet and visible spectrum and infrared spectra.Results show that the graphite powder was oxided,the structure of graphene oxide is layer structure.Next,graphene oxide and DMF were used to synthseize graphene quantum dots(GQDs)using a step solvent hot method.The morphology,structures and characters was characteerized by transmission electron microscopy,infrared spectrum,Raman spectrum and fluorescence spectrum.According to the results of GQDs in DMF is monodisperse system,the average particle size was 1.82 nm,has the rich oxygen containing functional groups,with green fluorescence,and the fluorescence intensity and position will change with the change of the excitation spectrum.4.Three kinds of GQDs-porphyrin(Tetrasodium-meso-tetra(4-sulfonatopheny-l)porphine dodecahydrate,(95%),Fe(?)meso-Tetra(N-Methyl-4-Pyridyl)porphine pentachloride and meso-Tetra(3-methoxy-4-hydroxyphenyl)porphine)composites were assembled by means of noncovalent interaction.The composites were characterized by ultraviolet spectrum and fluorescence spectrum analysis.The results showed that when The binding constants(K?)of GQDs were porphyrinsKa(GQDs-NaTSPP)=1.014×106,K?(GQDs-FeTMPyP)=6.268x 104 and Ka(GQDs-TMOHPP)=1.553×105,the GQDs combination of the three kinds of porphyrin with different ability:GQDs-NaTSPP>GQDs-TMOHPP>GQDs-FeTMPyP.