Synthesis, characterization and analytical separation of metal nanoparticles

This thesis mainly focuses in two parts. The first one is the synthesis and analytical separation of a water-soluble metal nanoparticle, N-acetyl-L-cysteine protected gold monolayer protected cluster (Au MPC). The as-prepared product was well characterized by different techniques. The crude Au MPC is a polydisperse spherical product with an average particle size of 1.7 +/- 0.5 nm.;Since the synthesized Au MPC product is polydisperse, an effective capillary electrophoretic (CE) technique for separating samples of Au MPC has been developed. The separation mechanisms of Au MPC in capillary zone electrophoresis suggest that the larger core sizes Au MPC emerge first from the capillary. The electrophoretic separation depends on pH, buffer concentration and organic modifiers. The run buffer containing 20% v/v ethanol provides the best separation for water-soluble Au MPC and it is attributed to the more significant difference in the charge-to-size ratio between the Au MPCs. An increase in applied voltage can reduce the run time of Au MPC separation with the sacrifice of resolution. The proposed CE method provides a powerful tool to evaluate and separate the water-soluble Au MPC products.;In order to efficiently fractionate larger amounts of MPC product, a novel and simple electrolyte-induced fractionation method has been proposed. The effect of electrolyte concentrations and the lipophilicity of the solution in fractionation were also investigated. Small gold nanoclusters, Au 10, Au11, Au12 and Au15, could be isolated from the Au10 to Au50 polydisperse Au MPC product under certain experimental conditions. The core sizes isolation was evaluated by their photophysical properties, migration orders in CE, and mass spectrometry. The electrolyte-induced fractionation assists in the study of the photophysical properties of smaller Au MPCs that are present with the larger Au MPCs in a polydisperse Au MPC product.;The second part is to explore the application and synthesis of a bimetallic core-shell nanoparticle. An easy and simple two-step reaction was employed to synthesize a new type of ligand-protected (homocysteine-protected) gold-coated iron oxide nanoparticle (homocys-Au-Fe3O4). Fe 3O4 nanoparticles were initially prepared and subsequently coated with Au layers under hot citrate reduction of HAuCl4. The citrate monolayer of the nanoparticles was place-exchanged with homocyteine molecules to produce the well dispersed homocys-Au-Fe3O4 nanoparticles. These homocys-Au-Fe3O4 nanoparticles have been fully characterized by different techniques. The homocys-Au-Fe 3O4 nanoparticles were coated with ultra-thin layers of Au atoms (∼0.5 nm) having an average diameter of ca. 12 nm. This investigation provides important insights into the design of new water-soluble bimetallic core-shell magnetic nanoparticles for biomedical, analytical and catalytic applications.