Fourier transform infrared wavenumber determination

Autoscaling can also be used when all of the variables have the same units and come from the same instrument. However, it can be detrimental if the total variance information is relevant to the problem being solved. For example, if one wants to do an exploratory chemometric analysis of a series of FTIR (Fourier transform infrared) spectra in order to determine the relative sensitivities of different wavenumbers (X-variables) to a property of interest, then it would be wise to avoid autoscaling and retain the total variance information because this information is relevant for assessing the sensitivities of different X-variables. 

Fourier transform infrared spectroscopy was also used to determine the chain end functionality. To determine the hydroxyl functionality, neopentyl alcohol was used to construct a calibration curve. The dissociated 0-H stretching vibration appears at 3643 cm as shown in Figure 5. The calibration curve for the methoxycarbonyl end group was obtained with the MHMDPO model compound, which showed Ae C=0 stretching vibration at the same wavenumber, 1720 cm". The results are summarized in Table I. 

Since FT-IR spectrometry is based on the interference of waves of light (or radiation), first an account of this phenomenon is briefly given, before explaining the Fourier transform method by which an infrared spectrum is obtained from a measured interferogram. Some characteristics of FT-IR spectrometry, namely, wavenumber resolution, measurable wavenumber region, and accurate determination of wavenumbers are discussed. To facilitate the understanding of the description, which inevitably requires some mathematical formulations, many illustrations are provided. 

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