Rayleigh Scattering Spectral Studies On Pt, HSA－SiW And (AuI4- Cationics)_n Nanoparticles And Its Application

Part IThe Pt nanoparticle is an important material of the scanning tunnel microscope (STM) nanoprobe and a preferable catalyst. Its catalytic activity is closely relative to the interfacial properties of the Pt particle. So that, its synthesis, characterization and application have a vital significance. In this paper, the Pt nanoparticles in liqulid phase were prepared by the microwave high-pressure liquid phase procedure, with the reaction condition of 3.4×10-3 mol/L sodium citrate -8.0×10-4 mol/L Pt(IV)- 0.04 mg/mL polyacrylamide(PAM)-850W-4min. And its absorption and the Rayleigh scattering spectra have been studied. The results show that the Pt nanoparticle exhibits spherical shape and its diameter is about 10nm. No absorption peak for Pt nanoparticle is observed in the visible light range of 400-800nm, and the absorption value increases with the wavelength decreasing. Its concentration in the range of 0.5-4.0×10-4 mol?L-1 Pt is linear to A300nm, A400nm, A450nm and A500nm value. This shows that its diameter is same. If Pt nanoparticles were diluted, it is also linear to A400nm and A500nm value in the range of 0.5-8.0×10-4 mol?L-1 Pt. The Pt nanoparticle colloid is stability and no precipitation was observed. Its Rayleigh scattering spectrum is mainly determined by the light source in the range of 4.0×10-5-4.0×10-4mol/L Pt. There are five Rayleigh scattering peaks at 400nm, 470nm, 510nm, 800nm and 940nm. When its concentration is more than 8.0×10-4mol/L Pt, the Rayleigh scattering light intensity becomes smaller owing to concentration scattering quenching effect.Part IIThe human serum albumin(HSA)is one of the main compositions of human blood plasma, it can combine with many metal ions. The heteropoly acid has the functions such as antibacterium, anti-AIDS virus and so on. It will surely act with HSA when it enters human blood. So that, it has significance to study the interaction between heteropoly acid and HSA. It has been reported that the interaction between HSA and metal ion or medicine molecule causing the fluorescence quenching was studied with the fluorescence of HSA from the molecule level. But the absorption of metal ion and medicine molecule at 290nm causing the fluorescence quenching of HSA wasn't considened in many references. The paper has studied the mechanism that silicotungstic heteropoly acid (SiW) caused the fluorescence quenching of HSA from the formation of nanoparticles level by the Rayleigh scattering, absorption spectra and transmission electron microscope. The results verified that an ion association nanoparticle in size of 50 nm exists in the HSA-SiW system in pH7.40 Tris buffer solution. That makes the fluorescence peak of HSA at 350nm quenched and the Rayleigh scattering (at 470nm) enhanced considerably. The effect that the absorption of SiW molecule caused the fluorescence quenching of HSA was neglected because its absorption at 290nm was very weak. This mechanism is that owning to the ion association molecule of HSA(SiW)n being formed through electric attraction between the positive charge amino group of HSA and the SiW anion, and the strong Vander Waals forces and hydrophobic forces among HSA(SiW)n molecules leading to the formation of [HSA(SiW)n]m associationnanoparticles, the fluorescence groups of HSA were wraped in the body of the nanoparticles. Results show that the formation of [HSA(SiW)n]m nanoparticles and the interface are main factor that caused the fluorescence quenching and Rayleigh scattering enhancement.Part IIIThe cationic surfantants are applied extensively owing to its good properties, so it is important to study its spectral characteristic. The absorption spectrum that the cationics can form micelles (nanodrops) at higher concentration of the cationics was reported. But untill now the study about ion association nanoparticle between the cationics and the inorganic anion wasn't reported. This paper studied the Rayleigh scattering spectrum of [AuI4]―-Cetyltrimethyl ammonium bromide(CTMAB) system and the effection with so...