Improved strategies for quantitative evaluation of atmospheric FTIR spectra obtained in open-path monitoring

Improvements in the quantitative evaluation of atmospheric Fourier-transform infrared (FTIR) spectra, obtained in environmental monitoring by using a bistatic spectrometer setup, are presented. Preprocessing of interferograms and spectral data was carried out to improve the photometric accuracy and wave-number scale reproducibility, necessary for reliable quantitative analysis. Univariate component analysis was optimized, and a refined strategy for multivariate analysis by least squares was set up. Special procedures were developed for the determination of benzene and of small molecules with resolved rotation–vibration fine structure. Results from field measurements, which were obtained by using the implemented subroutines for univariate and multivariate spectrum evaluation, are presented and discussed. © 1999 John Wiley & Sons, Inc. Field Analyt Chem Technol 3: 141–159, 1999