Fourier transform infrared optical remote sensing for monitoring airborne gas and vapor contaminants in the field.
TrAC, Trends Anal Chem 1994 Aug; 13(7):258-262
The theory behind the use of remote or optical open path/Fourier Transform infrared (OP/FTIR) spectroscopy for monitoring gas and vapor contaminants under field conditions was discussed. The general background and rationale for using OP/FTIR to monitor atmospheric pollutants were reviewed; the principles of OP/FTIR spectroscopy were described; and the analytical capabilities of OP/FTIR spectroscopy were summarized. OP/FTIR spectroscopy does not require the use of sampling lines, pumps, and manifolds. If software is available for a specific application, OP/FTIR can be used for real time monitoring and will produce results as accurate as those obtained by point measurement methods. Currently the detection limit for many compounds is on the order of 10 to 30 parts per billion if an optical path length of 100 meters and a 5 minute data acquisition time are used. The overall instrumental analysis accuracy is on the order of 15% to 25%, depending on the specific nature of the compound. Instrumental precision is considered good, around 5% for analyses of single compounds with no spectral interferences present. Examples of potential field applications of OP/FTIR spectroscopy were discussed. There are currently three areas that have received considerable attention in developing an OP/FTIR spectroscopic technique: measuring emission rates of pollutant gases from area and stack sources, measuring spills or leaks in the vicinity of waste sites or other sources of toxic gases, and workplace monitoring to detect overexposure to high levels of gases. Future improvements needed for OP/FTIR spectroscopy were discussed. These include developing a procedure to deal with interference from water vapor, improving the quality of reference spectra, developing more rugged instruments for field use and instruments that can be used to construct air contaminant concentration profiles.
NIOSH-Publication; NIOSH-Grant; Grants-other; Analytical-methods; Infrared-spectroscopy; Spectrographic-analysis; Analytical-instruments; Industrial-hygiene; Air-contamination
Environmental & Indust Health University of Michigan 1420 Washington Heights Ann Arbor, MI 48109-2029
Trends in Analytical Chemistry
University of Michigan at Ann Arbor, Ann Arbor, Michigan