Raman spectroscopy produces highly characteristic responses from all molecular species. It uses visible or near-IR radiation and thus is well suited for use with relatively inexpensive low-loss fiber optics. Because it is a scattering measurement, it is readily applied to samples in a variety of forms, including aqueous solutions, solids and slurries, and to samples in hostile environments. Potential problems relating to sensitivity and reproducibility have been addressed by selection of appropriate instrumentation and data treatment strategies. This report describes considerations affecting the use of fiber optic components in Raman measurements for quantitative analysis. Both bidirectional single fiber probe systems and unidirectional multifiber probes have been considered. Some results for in situ monitoring are reported. Reactants and products have been monitored during the synthesis of a conducting polymer. Spectra have been measured and quantitation carried out for a mixture of azo dyes in a flowing stream. Measurements have also been made on mixtures of solids and on organic films on a metal surface. Problems relating to representative sampling of nonuniform materials are considered. A Hadamard transform approach to obtain energy throughput and spatial averaging advantages is described.

Date Published: 1 May 1992
PDF: 10 pages
Proc. SPIE 1637, Environmental and Process Monitoring Technologies, (1 May 1992); doi: 10.1117/12.59327

Published in SPIE Proceedings Vol. 1637:
Environmental and Process Monitoring Technologies
Tuan Vo-Dinh, Editor(s)