*2.6. Infrared Spectroscopy (FTIR-ATR)*

FTIR spectra were obtained on a Perkin-Elmer Spectrum 2000 instrument by the attenuated total reflectance (ATR) technique. The spectra were recorded in the 4000–600 cm−<sup>1</sup> range with 16 scans at a resolution of 4.0 cm−<sup>1</sup> and an interval of 1.0 cm−<sup>1</sup> [23]. All the spectra were baseline corrected and normalized in an area, in order to make adequate comparisons.
