ABSTRACT
In the 20th century, analytical techniques that were based on the interaction of light with matter began to be used. The comparison between incident and transmitted light provides information on the characteristics of the analyzed sample. This chapter discusses: (1) the relationship between electromagnetic radiations and their effects, (2) the relationship between spectroscopic techniques and their obtained information, (3) the fact that functional groups −OH and −NH2 present an auxochromic effect on chromophore benzene, particularly compared to peak B, and (4) a comparison of ultraviolet–visible with fluorescence spectroscopies.
