We present a method for monitoring subtle (sub-wavenumber) dynamics within time-varying spectra. Peak fitting is performed for large numbers of spectra in a series, allowing for monitoring time evolutions of peak positions with high precision and confidence. Sub-wavenumber peak shifts due to physical or chemical changes in the sample can be monitored and their temporal evolution characterized. In surface-enhanced Raman scattering experiments, we were able to distinguish between slow photo-damage and fast conformational change dynamics. Fluctuations in peak positions of Raman spectra recorded from a single yeast cell indicated that no significant irreversible photo-damage occurred, but these fluctuations suggest changes in the trapping conditions or biochemical changes associated with the cellular machinery in the cell. The technique is particularly suitable for applications where dynamics of spectra are of interest.
Vol. 8, Iss. 3 Virtual Journal for Biomedical Optics
Zachary J. Smith, Che-Wei Chang, Latevi S. Lawson, Stephen M. Lane, and Sebastian Wachsmann-Hogiu, "Precise Monitoring of Chemical Changes Through Localization Analysis of Dynamic Spectra (LADS)," Appl. Spectrosc. 67, 187-195 (2013)