The Study On The Application Of Functional Nanoparticles In Metal Ions Determination

Owing to the unique optical, electrical and catalytic properties, nanoparticles materials have been widely applied in fields of biology, materials chemistry and medicine etc in recent years. The introduction of organic molecules onto nanoparticles surfaces not only provides their stability in different solvents, but also ideal surface functionalities, improve the selectivity in molecular recognition. In this thesis, based on the remarkable optical properties of nanoparticles, we have researched the synthesis and properties of functional nanoparticles in metal ion determination. The main contents are shown as follows:1. Functionalized quantum dot-based fluorescent probe for zinc ion. Prepared ZnS:Mn QDs capped N-acetyl-L-cysteine, which were characterized by fluorescence, UV-Vis, FT-IR spectroscopy and X-ray. At first the fluorescence quenching gradually with increasing concentration of S2’. Meanwhile the fluorescence intensity of ZnS:Mn QDs modified S2" was greatly enhanced in presence of Zn2+. The method was successfully developed for Zinc ion sensing, there was good linear relationship between relative fluorescence intensity and the concentration of Zn2+in the range of1.25μM to30μM, with a correlation coefficient (R) of0.997, the detection limit (LOD) is6.7×10-7mol· L-1. The possible mechanism was discussed.2. The water-soluble NAC-modified silver nanoparticles, which were uniform in aqueous solution, were prepared through chemical reduction method. It was found that NAC-Ag NPs got aggregated only with the concentration of Ni2+increasing, and the absorption spectra changed, and the response sensitively. This process was charaaterized by transmission electron microscopy (TEM) and Uv-vis spectroscopy. A simple and rapid sensor for Ni2+was developed.3. Through a previously reported method8Q5S-Ag NPs was prepared, which were stable and uniform in aqueous solution, were characterized by TEM, FT-IR and Uv-vis spectroscopy. It was clear that this modified Ag NPs can be utilized as a colorimetric sensor for Al3+. The possible mechanisms were discussed. 4. SAA-Ag NPs were synthesized using a commodity chemical sulfosalicylic acid as protective agent, via a simple chemical reduction method, the prepared silver nanoparticles were stable and uniform in aqueous solution. Based on Cd2+induced SAA-Ag NPs aggregation, a new method was successfully applied to the determination of Cd2+, implements the metal ions interact with silver nanoparticles.