Quantitative diffuse reflectance and transmittance infrared spectroscopy of nondiluted powders

An adaptation of Kubelka's general model of diffuse reflectance and diffuse transmittance of light to nonideal scattering samples is proposed. It is applied to quant. Fourier transform IR spectrometry of nondiluted surface-derivatized silica powders. Corrections of the measurements are introduced in order to take into account common problems that often prevent a truly quant. application of the DRIFTS anal. method. Effects on the measured data due to the background absorption of the sample and to the specular reflection on its surface are discussed and quant. cor. for. The possible existence of gradients of the optical properties of the powder medium is taken into account by a numerical adaptation of the model to inhomogeneities of the phenomenol. absorption and scattering coeffs. K and S. Model systems constituted of two types of silica powders of very different morphol. are prepd. Known concns. of mols. carrying a cyano functional group as chromophore were covalently anchored on the powder surface. Application of the adapted model gives a quite good description of the measured diffuse reflectance and diffuse transmittance in these cases where the simple Kubelka-Munk function fails.


Published in:
Applied Spectroscopy, 46, 12, 1874-1886
Year:
1992
Keywords:
Note:
Copyright 2003 ACS
CAPLUS
AN 1993:160261
CAN 118:160261
80-6
Organic Analytical Chemistry
73, 79
Inst. Chim. Phys.,Polytech. Fed. Lausanne,Lausanne,Switz. FIELD URL:
Journal
APSPA4
written in English.
Cyano group (detn. of, in powders, diffuse reflectance transmittance IR spectrometric); Powders (quant. diffuse reflectance transmittance IR spectrometric anal. of nondiluted); Silica gel Role: ANST (Analytical study) (quant. diffuse reflectance transmittance IR spectrometric anal. of nondiluted powd., LiChrosorb Si 100); Spectrochemical analysis (IR, Fourier-transform, of nondiluted powders); Spectrochemical analysis (IR, reflection, diffuse, Fourier-transform, of nondild. powders); Silica gel Role: ANST (Analytical study) (silylated, reaction products, quant. diffuse reflectance transmittance IR spectrometric anal. of nondiluted powd.)
Laboratories:




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