Instrumental Resolution Considerations for Fourier Transform Infrared Gas-Phase Spectroscopy

Abstract

Instrumental resolution has a significant effect on the performance of Fourier transform infrared (FT-IR) spectrometers used for gasphase analysis. Low-resolution FT-IR spectroscopy offers some valuable advantages compared with the traditional high-resolution FT-IR gas-phase spectroscopy, especially in nonlaboratory environments. First, high signal-to-noise ratio (SNR) spectra can be acquired in field conditions without the use of traditional liquid nitrogen-cooled detectors. Second, the dynamic range for quantitative analysis is larger for low-resolution spectroscopy than for high-resolution due to the lower absorbance values and lower noise levels. Third, spectral analysis speed is increased and data storage requirements are substantially reduced. The purpose of this study was to investigate the effect of instrumental resolution on FT-IR gas-phase analysis. The effects of spectral resolution on sensitivity, selectivity, accuracy, precision, spectral overlap, dynamic range, and nonlinearity are separately discussed.