Abstract: A method for correcting an infrared absorption spectrum comprises the steps of:—providing a measured infrared absorption spectrum from a sample,—determining a baseline correction curve by using at least one spectral interval in which an absorption quantity is expected to be null for at least two wavelength quantities,—subtracting the baseline correction curve from the measured infrared absorption spectrum, to obtain a first corrected absorption spectrum,—extracting at least one absorption band whose position is out of the fingerprint region,—comparing each extracted absorption band with the expected absorption band,—correcting the baseline correction curve in accordance with the results of the comparing step, to obtain a corrected baseline correction curve, and—subtracting the corrected baseline correction curve from the measured infrared absorption spectrum, to obtain a second corrected absorption spectrum.

Abstract: The present invention concerns a method for determining at least one absorption band in a spectrum, the method at least comprising the steps of:—providing a measured absorption spectrum from the sample,—providing a calculation spectrum,—from the calculation spectrum, extracting at least one absorption band,—calculating a residual spectrum by removing each extracted absorption band from the calculation spectrum, testing whether a predefined stop criterion is fulfilled by the residual spectrum,—if the stop criterion is not fulfilled, using the residual spectrum as the calculation spectrum and iterating the extracting step, the forming step, the calculating step and the testing step, and—if the stop criterion is fulfilled, outputting each extracted absorption band.