Lawrence Berkeley National Laboratory

Synchrotron-based infrared (IR) microspectroscopy and synchrotron-based x-ray fluorescence have been used to study chemical markers and profiles of latent human fingerprints. IR band intensities and band intensity ratios for functional groups of chemical molecules that are inherent to the experimental system are discussed in the context of molecular species that can be identified by comparison to infrared spectra that have been reported previously in the literature for identified components. The detection and quantitative analysis of electrolytes in the fingerprints is discussed. Mapping of chemical heterogeneities using spectral markers is presented and discussed. Changes in the chemistry of the fingerprint will be discussed in context of the aging process, which is reflected in the changes in the infrared spectra. The use of the technique for chemical and biological profiling of an individual "molecular fingerprint" is also discussed.