Heavy Metal Ions And Small Molecular Recognition Based On Functional Modification Nanoparticles

In recent years, new nanoparticles materials have been widely applied in the fields of biology, material chemistry and medical. The modification of organic ligands on the surface of the nanoparticles can enhance their water-solubility and recognizing selectivity. We have synthesized three nanoparticles which modified with different ligands and the quantitative methods of metal ions and small molecules were proposed here. The main contents are divided into four chapters as follows.In chapter1, the basic concepts and properties of quantum dots and metal nanoparticles were briefly described. And the research for recognizing of ions and small molecules was summarized based on the linked atoms between the nanopaticles and functional ligands.In chapter2, ZnS:Mn QDs were prepared based on the oil method and capped with Schiff base using ligand exchange. The presence of copper ion resulted in fluorescence quenching of quantum dots. A good linear relationship existed in the concentration range from2.50x10-7-6.25×10-5mol L-1with correlation coefficient of0.992. The limit of detection was1.11×10-7mol L-1.In chapter3, Silver nanoparticles functionalizd with iminodiacetic acid (IDA-Ag NPs) were prepared. The absorption spectrum and solution color of these nanoparticles (NPs) underwent dramatic changes on exposure to Pb(II) ions, with a new absorption peak appeared at650nm. there was a linear relationship between the intensity ratio A650/A396and the concentration of Pb(II) in the0.4to8.0μM concentration range, with a detection limit of13nM.In chapter4, Citrate-protected gold nanoparticles were prepared. The gold nanoparticles could quench the fluorescence of fluorescein based on their good extinction coefficient. And the fluorescence of fluorescein recovered with the addition of cysteine which contains thiol groups. Based on this principle, a simple and rapid determination method for cysteine was establisded.