恒温法制备纳米银胶及其NIR-SERS活性研究

Preparation and NIR-SERS of Nano-Silver Colloids by Constant-Temperature Method

在恒温条件下(80℃)加热硝酸银和柠檬酸三钠混合液制得纳米银胶。将混合液66mL分别加热60,90,120,150,180和210分钟制得六个不同时间的纳米银胶样本。用紫外-可见(UV-Vis)分光光度计对上述6个样品进行检测,通过UV-Vis吸收光谱分析了纳米银胶中纳米银颗粒的粒径和粒径分布变化情况。同时使用激发光波长为785nm的便携式拉曼光谱仪,以结晶紫(1×10^(-6) mol/L)作为探针分子对加热不同时间的纳米银胶进行近红外表面增强拉曼散射(NIR-SERS)活性研究。最后分析了激光功率和银粒子浓度对结晶紫NIR-SERS光谱的影响。

Six kinds of nano-silver colloids were prepared by constant-temperature method. The mixture aqueous solution of silver nitrate and trisodium citrate was divided into six parts and heated at different time（60,90,120,150,180 and 210 min,80℃）. These samples were tested by the ultraviolet-uisible spectrophotometer and the UV-Vis spectra were used to analyse the changes of the Ag nanoparticles size and distribution. To test the NIR-SERS activity of the nano-silver colloids, crystal violet（1× 10^-6 mol/L） was used for probe molecules. The NIR-SERS activity of nano-silver colloids were discussed and the NIR-SERS spectra of crystal violet in six different samples were obtained by means of an Ocean Optics Portable Raman spectrometer equipped with an air-cooled diode laser（785 nm）as excitation source. At last, the effects of laser power and nanoparticles concentration for the NIR-SERS spectra of crystal violet were discussed.