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Fluorescence and Raman spectra on painting materials: reconstruction of spectra with mathematical methods
Author(s) -
Osticioli Iacopo,
Zoppi Angela,
Castellucci Emilio Mario
Publication year - 2006
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1587
Subject(s) - raman spectroscopy , deconvolution , fluorescence , laser , spectrometer , analytical chemistry (journal) , coherent anti stokes raman spectroscopy , spectral line , optics , chemistry , excitation , raman scattering , background subtraction , materials science , physics , pixel , chromatography , quantum mechanics , astronomy
SERDS (shift excitation difference spectroscopy) and SSRS (subtracted shifted Raman spectroscopy) methods were applied for fluorescence‐background rejection in the Raman spectra of colored materials. These techniques are based on the assumption that the fluorescence contribution can be completely eliminated by subtracting two Raman spectra acquired at two shifted laser excitation frequencies. For the SERDS method a micro‐Raman experimental apparatus coupled with a tunable diode laser (central emission at 684 nm) was set up. SSRS measurements were made on a commercial micro‐Raman instrument; in this case the shifted spectrum was obtained by moving the spectrometer grating. Raman spectra were then reconstructed by applying the difference deconvolution method that automatically converts the difference signals in Raman peaks through a deconvolution operation. These techniques were tested on two reference colors (ultramarine and 6,6′‐dibromoindigotine) and two colored samples of unknown composition (a Pompeian pink powder and a blue paint from a XVII century painting). Fluorescence‐background subtraction and the following operation of spectra reconstruction took place successfully with no errors in Raman peaks, width and wavenumber position. In addition, even weak spectral details were revealed favoring the comparison with reference data for a molecular identification. Copyright © 2006 John Wiley & Sons, Ltd.