ABSTRACT
98Infrared (IR) spectroscopy has assumed a premier place in the array of tools that the pharmaceutical scientist can bring to bear on a problem today. Since the 1950s, when commercial instrumentation became widely available, the infrared spectrophotometer has become a fixture in nearly every research and quality control laboratory. Infrared spectral determinations are used for a variety of purposes. Perhaps most common is that of identification, usually by comparing the spectrum of a sample to that of an authentic reference standard. Spectra are as routinely reported as are melting points for newly discovered antibiotics—valued for the unique “fingerprint” they provide, as well as for the structural information to be gleaned from their study. Quantitative analyses are run using infrared measurements and a host of mechanistic and conformational-structural information can be obtained from infrared studies. In this chapter we will briefly dwell on the nature and origins of infrared spectra, subjects that have been treated in detail in a number of places, and focus instead on the variety of ways in which this region of the spectrum has been put to use in the study of antibiotics and their properties.
