In Fourier transform absorbance spectroscopy, several types of baseline errors may be caused by the variations in the optical system, especially in the interferometer. The nature and causes of these errors have been studied. Furthermore, a method to eliminate the effect of these errors on multicomponent analysis is introduced. The nature of the errors has been experimentally verified, and a practical example of the use of the correction method is presented.
I. K. Salomaa and J. K. Kauppinen, "Origin of and Compensation for the Baseline Errors in Fourier Transform Spectra," Appl. Spectrosc. 52, 579-586 (1998)