Room-temperature Phosphorescence (Flsorescence) Sensor Based On Manganese Doped Zinc Sulfide Quantum Dots For Heavy

Quantum dots are the size of particles in the range1-l00nm, isa novel with unique optical properties of nano semiconductormaterial, for its excellent optical properties, has been in chemicalsensing, cell imaging, biological labeling, life long time monitoringand tracing in vivo aspects show unique advantages, become a novelfluorescent probe for promising more than organic dyes, and has beenin biology, physics, chemistry, medicine and other aspects have madea series of research results. Exploration of fluorescent sensorsrecently more and more studies focus on the quantum dots, thephosphorescence properties of the quantum dot is rarely concerned.Small changes in the surface of quantum dots will change thechemical or physical properties of the optical properties of quantumdots, the quantum dots detection has been widely used in all kinds ofthings. In this paper, the main research contents are as follows:(1)3-MPA to as the stabilizer3-mercaptopropionic acid, wassynthesized in aqueous solution of water soluble Mn doped ZnSquantum dots. By transmission electron microscopy (TEM) of the Mndoped ZnS quantum dots were characterized. The results show thatthe quantum dots synthesized with uniform size, spherical, and thediameter of about3.5nm, compared with ZnS quantum dots is more stable, and the optical properties of quantum dots have better.Quantum dots with the excitation wavelength of295nm and emissionwavelength was590nm.(2) Room temperature phosphorescence properties of Mn dopedZnS based on quantum dots, a new method is simple, rapid, highsensitivity and detection limit of cadmium ion in aqueous solution inthe detection of low. In pH7PBS buffer medium, adding Cd2+Mndoped ZnS quantum dots system phosphorescence was found, therewas a good linear relationship between the concentration of strengthwith the change of Cd2+, the linear range was0.08-8M, the detectionlimit of the method was0.38M. The spectral characteristics of thefluorescence spectra and UV of quantum dot structures and thesolution absorption spectra and resonance, and the possiblemechanism of Cd2+recognition are discussed. The method wasapplied to the detection of Cd2+in water, the recovery rate was93.2-97.1%.(3) The same interaction of Mn doped ZnS quantum dots modifiedby MPA and mercury ions were carried out based on the detection, anew method for the detection of mercury ion in aqueous solution atroom temperature phosphorescence properties of doped quantumdots. The method to measure the linear range for mercury ion was0.04-8M, the detection limit was0.35M, the correlation coefficient is0.9930.(4)The use of Mn doped ZnS quantum dots MPA modified withbovine serum albumin(BSA) fluorescence properties of Mn dopedZnS quantum dots/BSA nanocomposites were synthesized forthe detection of Cu2+, results show that, in pH7PBS buffer, with the fluorescence intensity of Mn doped into ZnS quantum dots/B-SA the nanocomposite of Cu2+decreases, concentration showed agood linear relationship with the quenching intensity of Cu2+, thelinear range of6.4-518.4M, the line are quation was F=1.0497+0.007C (M), the correlation coefficient was0.986, the detection limitwas0.29M.