Infrared and Raman Microspectroscopy: An Overview of their Use in the Identification of Microscopic Particulates

The recent coupling of infrared and Raman spectrometers with microscopes has provided the analyst with two very powerful new tools for identification of microscopic particulates. Unlike other analytical tools, these microspectroscopic techniques yield molecular, as opposed to elemental, information. Both infrared and Raman microspectroscopy are reviewed with respect to their historical development and their respective advantages, limitations and capabilities. The two methods are then discussed in terms of their complementarity in solving chemical identification problems, and it is shown that both methods are often needed for complete sample characterization. Finally, their application to the identification of microscopic particulates is illustrated by two case studies: identification of solder flux residue contamination and characterization of various dust particles.