Quantitative infrared spectroscopic fundamentals

Near-infrared (NIR) spectra of water-methanol mixtures are examined to demonstrate the fundamental aspects of calibration. These spectra are used because they present unique challenges to calibration. Another reference NIR data set is also briefly evaluated. The reader should remember that the information presented is generic and applies to all calibration situations, not just spectroscopic data. Additionally, for discussion purposes, the quantitative information for the target analyte will be concentration. However, other chemical or physical properties can also be modeled. Throughout this chapter, unless noted otherwise as in Sections 5.3 and 5.4, it will be assumed that the described models have had the intercept term eliminated. The easiest way to accomplish this is to mean-center the data. 

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