FTIR and Raman studies of structure and bonding in mineral and organic-mineral composites

Spectroscopy techniques, such as Fourier transform infrared (FTIR) and Raman, offer methodologies that overlap and expand X-ray diffraction and transmission electron microscopy (TEM) analyses and help gain new insight into mechanisms of biomineralization. FTIR and Raman spectroscopy techniques measure the molecular environment of asymmetrically and symmetrically vibrating bonds, respectively. As such, these techniques have widely been used to gain information on mineral content, phase, and orientation as well as chemical composition of associated organic matrices like collagen, chitin, or lipids. The traditional coupling of optical microscopes to the newer generation FTIR and Raman spectrometers has enabled these analyses to be performed on samples with 0.1-20 μm spatial resolution. Herein, we briefly discuss the basis and protocol for effective measurements using vibrational spectroscopy by taking two systems from our own research as examples.