Preparation Of Gold Nanoparticles And Its Application In Spectral Analysis

Gold nanoparticles(GNPs), due to their unique optical and chemical properties, have been used widely in biological detection, biomarkers and surface enhanced Raman spectroscopy. And the unique properties of surface plasmon resonance of GNPs have also attracted the attention of many researchers. The surface plasmon resonance(SPR) mechanism is based on the development of visual sensing schemes caused by the binding-induced aggregation of spherical GNPs. The SPR absorbances are extremely sensitive to the chemical nature, size, and shape of the GNPs, as well their interparticle distances and the nature of their surrounding media. Currently, GNPs have extensively been used as analytical probes in analysis with biological molecules and heavy metal.In this paper, the spherical GNPs were synthesized by seed growth method. The applications of the as-prepared nanoparticles were not limited by solution p H, and it is easy to perform surface modification. In addition, they possess good performance as for their SERS activity. On this basis,the detection of glutathione and heavy metal ions was carried out by using functionalized gold nanoparticles. All the research work are outlined as follows:(1) First of all, by changing the amount of each reactant in the growth solution, the spherical gold nanoparticles were prepared by seed growth method at room temperature. At the same time, the prospect of this method in the application of the SERS study was investigated.(2) In the second part, reduced glutathione was detected by chemic and optical feature of gold nanoparticles. The interaction between GSH and gold nanoparticles was studied,through the covalent combination with the –SH group of GSH molecules, resulted in the absorption peak of gold nanoparticles at 540 nm shifts to the 700 nm. On this basis, a new rapid and simple method using ultra-visible spectrophotometric to determining reduced GSH was established. At the optimal conditions, GSH can be selectively determined in the range of 0.17μM(R=0.98588) with the detection limit of 0.17μM. Many relative amino acids will not interfere with the determination.(3) In the third part of the paper, under the condition of natural p H,a novel strategy for using gold nanoparticles modified with reduced glutathione(GSH) for sensing heavy metalsions(Cu2+) was reported. The GSH-GNPs can bind with Cu2+ more selectively over other metal ions(Fe3+、Ca2+、Zn2+、pb2+、Hg2+、Na+、K+), leading to a prominent color change. The obtained results proved that this method achieved high sensitivity with low interference.