硫代水杨酸修饰的CdSe/ZnS纳米晶的合成及应用研究

以硫代水杨酸作为修饰剂,合成了水溶性的CdSe/ZnS纳米晶.合成最佳条件为:CdSe与包覆层ZnS摩尔比为1∶8,pH值为11.00、回流时间为45 min、回流温度为80℃.从透射电子显微镜看到该纳米晶外观是独特的树枝形;紫外吸收光谱和荧光光谱表明CdSe/ZnS纳米晶比单一的CdSe纳米晶具有更好的发光特性;荧光强度在3个月内变化不大.在最佳实验条件下,将合成的CdSe/ZnS与牛血清白蛋白(BSA)作用,测得体系相对荧光强度与BSA质量浓度呈线性关系,线性响应范围为2.56～15.0 mg/L,线性方程为ΔF=101.17C-11.29(C为BSA质量浓度,单位是mg/L),R=0.996 2,检出限为0.64 mg/L.

SYNTHESIS AND APPLICATION OF CdSe/ZnS NANOCRYSTALS MODIFIED BY THIOSALICYLIC ACID

The water-soluble CdSe/ZnS nanocrystals were synthesized using a small organic molecule with benzene ring (thiosalicylic acid) as modifier. The optical properties of CdSe and CdSe/ZnS were studied by fluorescence and UV-Vis absorption spectroscopy. The more remarkable enhancement of emision intensity for CdSe/ZnS nanocrystals was observed than for CdSe nanocrystals. The optimal conditions for synthesis are with a molar ratio of CdSe and ZnS of 1:8, pH 11.0 and refluxing for 45 min at 80 0C. The fluorescence intensity has been stable for 3 months. The shape of CdSe/ZnS nanocrystals showed unique dendritic structure under TEM. Under the optimal conditions, the fluorescent intensity in the system of CdSe/ZnS NCs-BSA is linearly proportional to the concentration of BSA from 2.56 to 15.00 mg L-1. The linear equation is F=101.2C-11.3(C, mg L-1), R＝0.9962, with a detection limit of 0.64 mg L-1.