QUANTITATIVE-ANALYSIS OF METABOLIC GASES BY MULTICHANNEL RAMAN-SPECTROSCOPY - USE OF A NEWLY DESIGNED ELLIPTIC-SPHERICAL INTEGRATION TYPE OF CELL HOLDER

We describe the quantitative analysis of some metabolic gases by multi channel Raman spectroscopy. Raman spectra were measured for air, aceto ne, ammonia, carbon dioxide, and mixed gas consisting of acetone, ammo nia, and air. We designed a new elliptic-spherical integration type of cell holder to obtain the Raman spectra of gases with a high signal-t o-noise ratio. Concentrations of acetone, ammonia, and carbon dioxide were determined by the peak intensities of Raman bands at 2940, 3228, and 1385 cm(-1) respectively. To compensate for the fluctuations of Ra man intensities caused by several factors, such as the fluctuations of laser power, the peak intensity of a band at 2324 cm(-1) due to nitro gen gas was used as an internal intensity standard. The correlation co efficient between the corrected Raman intensity at 2940 cm(-1) and the concentration of acetone was calculated to be 0.984 for a concentrati on range of 2-12 ppm. The detection limit of acetone gas was found to be 2 ppm. (C) 1998 Optical Society of America.