Effects of Light-Scattering Coefficient of Adsorbent in Diffuse Reflectance Spectroscopy of Dye-Doped Microparticles

Diffuse reflectance spectroscopy on polymer particles and silica gels adsorbing tris(2, 2′-bipyridine)ruthenium(II), Ru(II), was conducted to elucidate the shape and size effects of an adsorbent on the spectrum. The diffuse reflectance light intensity (f(r∞)) was linearly correlated with the amount of the complex ([Ru(II)]) adsorbed on spherical polymer beads, amorphous-, or spherical-shaped silica gels as low as [Ru(II)]=10-8mol/cm3. However, the slope of a f(r∞) vs. [Ru(II)] plot was different between the adsorbents. The results were explained in terms of the different light scattering coefficient between the adsorbents, originating primarily from the different shape and size of the adsorbent.This study was partly supported by a Grant-in-Aid from the Ministry of Education, Science, Sports and Culture (08404051)