Interrelationships between sensitivity and selectivity measures for spectroscopic analysis

Quantitative analysis based on spectroscopic data often uses the matrix equation R = CK + E, which is the K-matrix form of the Beer-Lambert law. This equation's utility depends on the character of K's numbers. The quality of these numbers is often discussed by referring to how strongly components respond to measured wavelengths and the extent one component responds toward measured wavelengths compared to other components, i.e. by referring to the sensitivity and selectivity of the used wavelengths. Over the years, various measures for quantifying sensitivity and selectivity at the local (analyte specific) and global (all analytes simultaneously) levels have been put forth with varied degrees of success. This tutorial introduces and discusses many of the commonly used local and global measures and establishes interrelationships between them. It is hoped that this presentation will give the user a better understanding of their utility and drawbacks, as well as provide a background for future work in the assessment of spectroscopic information.