Page 286 - Handbook of Instrumental Techniques for Analytical Chemistry

276 Handbook of Instrumental Techniques for Analytical Chemistry

Figure 15.18 Optical diagram of a diffuse reflectance Figure 15.19 FTIR diffuse reflectance spectra of silica
accessory. (Reprinted by permission of Harrick gel samples. (a) 200 °C pretreated silica, (b) HMDS
Scientific Corporation.) pretreated silica, and (c) 600 °C pretreated silica.
(Reprinted by permission from Spectroscopy, Vol. 9, No.
8 by J. P. Blitz and S. M. Augustine, © 1994 by Advan-
star

is accomplished by driving microscope stages across the film cross-section while mapping the concen-
tration of functional groups that represent characteristics of each component. This type of infrared im-
aging technique can be more effectively carried out with a computer-controlled, two-dimensional
motorized stage and provides a systematic, nondestructive evaluation of sample composition on a mi-
croscopic scale.

Nuts and Bolts

Relative Costs
Dispersive $$ to $$$
FT $$$ to $$$$
GCIR $$$
PAS $$$
IR microscope $$ to $$$
Reference spectra $ to $$