Abstract: The sol-gel method was used successfully for the preparation of nano-sized silica gel suspension. A fluorophore -naphthyl group was introduced on the surface of silica gel particles by using surface chemical modification. In the study of steady state fluorescence spectrum, it was seen clearly that the naphthyl groups on the particle surface were able to reorganize in different solvents. And in a certain condition the excimer fluorescence of naphthyl group may be observed evidently. The surface fluorescence quenching of particles by different transition cations was studied. It was found that only Cu2＋ cation showed itself very strong ability of quenching the surface fluorescence of studied particles. But for other metal cations almost no any quenching effect was observed. The excellent recognition of Cu2＋ cation of this system provides a possibility to develop a new fluorescence sensor for Cu2＋ cation detection.

Key words: Nano-materials, Sol-gel method, Surface chemical modification, 　Transition metal cations, Fluorescence chemical sensor