Semiconductor nanoparticle fluorescent reagent and fluorescence determination method

#1. Technical Field

#The present invention relates to a fluorescent reagent using semiconductor nanoparticles, and a fluorescence determination method using semiconductor nanoparticles.

#2. Background Art

#FIG. 1 shows the absorption spectra of semiconductor nanoparticles.

#FIG. 2 shows the correlation between single color irradiation time and fluorescent spectrum of CdS nanoparticles.

#FIG. 3 shows the fluorescence spectra of semiconductor nanoparticles.

#Herein, CdS nanoparticles and ZnS nanoparticles are referred to for description of the method for preparing semiconductor nanoparticles according to the present invention.

#In a semiconductor particle, the proportion of its surface area to its volume is very large, and thus semiconductor nanoparticles tend to coalesce very easily. Therefore, in order to allow the semiconductor nanoparticles to exist stably, measures have to be taken to prevent them from colliding or fusing with each other. A variety of measures have been devised so far, which can be roughly divided into two types. One is the physical isolation of the semiconductor nanoparticles by incorporating them into a solid matrix and a polymer matrix. The other is the inactivation of the particle surface by chemically modifying a metal-ion site on the particle surface with a low-molecule organic matter having a high capacity for forming a complex with the metal-ion site. Based on the latter concept, hexametaphosphate was employed as the stabilizer for the present example.

#1000 ml of an aqueous solution of sodium hexametaphosphate (0.1 mmol) and cadmium perchlorate (0.2 mmol) was prepared and adjusted to pH 10.3. Nitrogen gas was bubbled into the solution, and then hydrogen sulfide gas (0.2 mmol) was injected into the solution while stirring vigorously. Thereafter, stirring was conducted for a while, during which time the solution changed from optically transparent and colorless to optically transparent yellow.