Indiana Section of the Society for Applied SpectroscopyIndiana Section of the Society for Applied Spectroscopy
2002-2003 Seminar Abstracts
Laser-based Opical and Chemical Imager (LOCI): Marriage of Spectroscopy with Mass Spectrometry
Dr. Jill Scott
Idaho National Engineering and
Environmental Laboratory
Idaho Falls, ID 83415
http://subsurface.inel.gov/Information/Newsletter/Vol3Iss2/mass_spec.asp
Our primary focus has been development of the laser-based optical and chemical imager (LOCI) that provides optical and chemical imaging of complex, heterogeneous sample surfaces. LOCI combines a Fourier transform mass spectrometer (FTMS), unique laser-scanning system, custom optics for fluorescence detection, and software for automated data acquisition and analysis. A key feature of LOCI is the unique laser-scanning device that provides high spatial reproducibility for depth profiling and has been automated to provide imaging capabilities. The excellent reproducibility and wavelength independence of the laser-scanning device affords the opportunity to interrogate the same sample surface via optical spectroscopy prior to obtaining mass spectra. Interpretation of mass spectra has also been automated using a Fuzzy-logic inference engine, which also produces the surface maps. Our current imaging interests include characterizing microbe affinities for specific mineral phases in basalt and determining contaminant speciation.
A second focus is characterization and reactivity of gas-phase moieties derived from surfaces. Usually, the ability of the FTMS to select and trap ions is employed to study traditional ion/molecule reactions (MSn). However, mass spectrometry cannot give electronic or structural information directly. Therefore, we have incorporated an optical detection system for gas-phase ions trapped in the FTMS. The high resolution and mass accuracy of the FTMS is critical because conclusions regarding fluorescence behavior depend on explicitly identifying the gas-phase species.
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