Authors: Limin Shao Christopher W Roske Peter R Griffiths
Publish Date: 2010/04/23
Volume: 397, Issue: 4, Pages: 1521-1528
Abstract
Openpath FTIR spectra of lowconcentration releases of diethyl ether were measured both when a glycol fog was passed into the infrared beam and when large water droplets from a lawn sprinkler were sprayed into the beam It was shown that the glycol fog for which the droplet size was much less than the wavelength of the infrared radiation gave rise to a significant interference such that partial least squares PLS regression would only yield reasonable values for the ether concentration if background spectra in which the glycol fog was present were included in the calibration set On the other hand target factor analysis TFA allowed the presence of the ether to be recognized without precalibration When large water droplets were present in the beam any infrared radiation entering the droplet was completely absorbed so that both PLS and TFA would yield accurate results
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