Fourier-transform infrared (FTIR) microscopy is a modern analytical technique able to provide a molecular imaging of a complex sample. With this technique, based on the absorption of IR radiation by vibrational transitions in covalent bonds, unique images with a high spatial resolution can be obtained from a sample. The spatial resolution of an infrared microscope, as defined by the diffraction limit, is about 2λ/NA, i.e., from 3 to 4 times the wavelength depending by the NA (numerical aperture) of the instrument. In these last decades the availability of solid-state array detectors revolutionized the fields of molecular spectroscopy and chemical imaging. Nowadays, 2-dimensional IR detectors, Focal Plane Arrays (FPAs), coupled to synchrotron radiation sources allow achieving the highest sensitivity and the highest resolution of molecular imaging in a short time. FPA arrays, composed by small IR detectors (pixels), allow the acquisition of thousands of IR spectra simultaneously and generate mid-IR images with high resolving power, thus improving performances of IR imaging systems equipped by conventional IR sources. A microscope equipped with a FPA has no apertures and its sensitivity is associated to the pixel size: the effective “aperture” of the optical system. FPAs enable different imaging modalities with a resolution of a few microns (depending on the pixel size and magnification of the objective). Massive and fast data collection is possible with a drastic reduction in the acquisition time compared to a confocal geometry. Experiments performed with conventional instrumentations have clearly shown that combining the sensitivity and the speed of read-out of the last generation of FPAs the time may scale down from hours to minutes (Barghawa and Lewin, 2001, Petibois et al., 2008). H-C-O functional groups are characterized by highly polar bonds and absorb infrared radiation with high efficiency, therefore FTIR micro-spectroscopy may be used to qualitatively and quantitatively measure these elements in geological materials (both minerals and glasses) with a high-spatial resolution (Wysoczanski and Tani, 2006; Della Ventura et al., 2009). We will present here and discuss new applications of infrared imaging, with particular reference to the distribution and speciation of H and C in a variety of mineralogical samples, including single-crystals (microporous minerals, NAMs, fluid inclusions) and thin sections, as well as the use of FTIR imaging in high-temperature studies. References Barghawa, R. and Lewin, I. (2001) Anal. Chem. 73, 5157-5167. Petibois C., Piccinini M., Cestelli-Guidi M.A., Déléris G. and Marcelli A. (2009) Nature Phot. 3, 177 Della Ventura, G., Bellatreccia, F., Cesare, B., Harley, S., Piccinini, M. (2009) Lithos, accepted. Wysoczanski, R., Tani, K. (2006) J. Volcan. Geoth. Res., 156, 302-314.

DELLA VENTURA, G., Bellatreccia, F., Marcelli, A., Cestelli Guidi, M., Piccinini, M. (2009). FTIR imaging: new opportunities in earth sciences. In Settimo Forum Italiano di Scienze della Terra Epitome (pp.430-430).

FTIR imaging: new opportunities in earth sciences

DELLA VENTURA, Giancarlo;BELLATRECCIA, FABIO;
2009-01-01

Abstract

Fourier-transform infrared (FTIR) microscopy is a modern analytical technique able to provide a molecular imaging of a complex sample. With this technique, based on the absorption of IR radiation by vibrational transitions in covalent bonds, unique images with a high spatial resolution can be obtained from a sample. The spatial resolution of an infrared microscope, as defined by the diffraction limit, is about 2λ/NA, i.e., from 3 to 4 times the wavelength depending by the NA (numerical aperture) of the instrument. In these last decades the availability of solid-state array detectors revolutionized the fields of molecular spectroscopy and chemical imaging. Nowadays, 2-dimensional IR detectors, Focal Plane Arrays (FPAs), coupled to synchrotron radiation sources allow achieving the highest sensitivity and the highest resolution of molecular imaging in a short time. FPA arrays, composed by small IR detectors (pixels), allow the acquisition of thousands of IR spectra simultaneously and generate mid-IR images with high resolving power, thus improving performances of IR imaging systems equipped by conventional IR sources. A microscope equipped with a FPA has no apertures and its sensitivity is associated to the pixel size: the effective “aperture” of the optical system. FPAs enable different imaging modalities with a resolution of a few microns (depending on the pixel size and magnification of the objective). Massive and fast data collection is possible with a drastic reduction in the acquisition time compared to a confocal geometry. Experiments performed with conventional instrumentations have clearly shown that combining the sensitivity and the speed of read-out of the last generation of FPAs the time may scale down from hours to minutes (Barghawa and Lewin, 2001, Petibois et al., 2008). H-C-O functional groups are characterized by highly polar bonds and absorb infrared radiation with high efficiency, therefore FTIR micro-spectroscopy may be used to qualitatively and quantitatively measure these elements in geological materials (both minerals and glasses) with a high-spatial resolution (Wysoczanski and Tani, 2006; Della Ventura et al., 2009). We will present here and discuss new applications of infrared imaging, with particular reference to the distribution and speciation of H and C in a variety of mineralogical samples, including single-crystals (microporous minerals, NAMs, fluid inclusions) and thin sections, as well as the use of FTIR imaging in high-temperature studies. References Barghawa, R. and Lewin, I. (2001) Anal. Chem. 73, 5157-5167. Petibois C., Piccinini M., Cestelli-Guidi M.A., Déléris G. and Marcelli A. (2009) Nature Phot. 3, 177 Della Ventura, G., Bellatreccia, F., Cesare, B., Harley, S., Piccinini, M. (2009) Lithos, accepted. Wysoczanski, R., Tani, K. (2006) J. Volcan. Geoth. Res., 156, 302-314.
2009
DELLA VENTURA, G., Bellatreccia, F., Marcelli, A., Cestelli Guidi, M., Piccinini, M. (2009). FTIR imaging: new opportunities in earth sciences. In Settimo Forum Italiano di Scienze della Terra Epitome (pp.430-430).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/186225
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