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Keywords:

  • SERS;
  • DFT;
  • Ag electrode;
  • vibrational analysis;
  • alizarin

Abstract

This paper presents the application of Raman spectroscopy (RS) for the structural study of alizarin adsorbed on a metallic surface. As a biologically active molecule, alizarin has remarkable antigenotoxic activity like other anthraquinone dyes. Alizarin is highly fluorescent and that limits the application of RS as an investigation method; however, the Fourier transform-RS (FTRS) can be applied since the near-infrared excitation line lies far away from the absorption region of alizarin. The surface enhanced-RS (SERS) technique also makes the fluorescence quenching possible. In this work, monolayers of alizarin were deposited on the surface of an electrode by the immersion of silver substrates in methanolic solution of the analyte. From such prepared samples, by using the excitation of 488, 514.5 and 647.1 nm the Raman spectra were registered. Depending on the excitation line, SERS or surface-enhanced resonance Raman scattering (SERRS) spectra of alizarin were observed. The interpretation of experimental data was supported by theoretical calculations. Copyright © 2008 John Wiley & Sons, Ltd.