Researches Of Preparation Of Aqueouse Quantum Dots For Analytical Probe Of Bisphenola

Semiconductor nanoparticles, also known as quantum dots, with a surface effect, quantum confinement effect, the macro-quantum tunnel effect, size effect and coulomb blockade effect, it has many excellent spectral characteristics. Traditional organic dyes and fluorescent probes, compared with the excitation spectrum wide distribution for bands, narrow emission spectra, emission wavelength tunable, and anti-bleaching ability and so on. They are specific kinds of nanoparticles newly developed in recent years.Synthesis and application of quantum dots have generated a tremendous amount of interests in the fields of nanoanalytical chemistry and bioanalytical chemistry.In this thesis, we deal with the preparation of newly high fuorescence QDs and research of its microstructure and optical properties were finished. A novel method for the trace determination of estrogens bisphenol A (BPA) in food packing materials was proposed.The major fruits are listed below:1. Cysteamine stabilizered aqueous CdTe quantum dots were prepared by hydrothermal water soluble and characterized with UV-Vis absorption spectra, fluorescence emission spectra, infrared spectra, transmission electron microscopein and X-ray diffraction analysis. Based on the characteristic fluorescence quenching of the CdTe QDs by BPA, a simple rapid, sensitive and selective quantification method was presented. Under optimum conditions, the linear range was from 4×10-9 to 4.5×10-7 mol/L, an excellent correlation coefficient was 0.996 and the limit of detection was 1×10-9 mol/L. The proposed method has first been applied to the determination of BPA in nursing bottle samples.2. CdSe QDs coated with sodium dimercaptosulphonate were first synthesized directly in aqueous solution. The change regularity of UV-Vis absorption spectra and fluorescence emission spectra of BPA on CdSe QDs for BPA was studied. CdSe QDs was characterized with transmission electron microscopein, X-ray diffraction and infrared spectra. Based on the characteristic fluorescence enhancing of the CdSe QDs by BPA, a simple rapid, sensitive and selective quantification method was presented. The BPA digestion in PC bottle and paper cups were effected by tempeature, heated time, applied times, feeder types, simulacrum in PC bottle, plastic bottle.The linear range was from 4×10-9 to 4.5×10-7mol/L, an excellent correlation coefficient was 0.998 and the limit of detection was 1.5×10-9 mol/L. The proposed method has first been applied to the determination of BPA in water bottle of PC and paper cups.3. The Ag quantum dots have first been obtained directly in aqueous solution using 1-methyl-5-mercapto-1,2,3,4-tetrazole as stabilizing agent. The transmission electron microscopy and X-ray diffraction results characterized microstructure and crystalline form of Ag QDs. Based on the characteristic UV-Vis absorption of mixed solution of Ag QDs and BPA, a simple rapid, sensitive and selective quantification method was presented. The linear range was from 4×10-12 to 2×10-9 mol/L, an excellent correlation coefficient was 0.993 and the limit of detection was 4×10-12 mol/L.The proposed method has first been applied to the determination of BPA in disposable lunch boxes samples.