In ordertoestablishnewdiscriminatingcriteriaforthestudied
substances,aspecific methodologybasedonthe bandsmorphology
andprofile, andinvolvingmultivariateanalyseswassetup.Itcanbe
described asfollows.The first stepconsistedinchoosingthemost
appropriatespectralregiontoprocess.Althoughthemostspecific
bandsarelocatedinthe fingerprintregion(200–1800cm−1) ofthe
spectra,theyareweakespeciallyforRamanandthereforemostlikely
todisappearorbemodified incaseofabadsignal-to-noiseratio;
with alsofurthercomplicationtostudybandprofiles (Fig. 1). How-
ever,theCHstretchingvibrationbandinthe2900cm−1 areaisthe
mostintenseregionontheRamanspectra,andalwaysintenseonthe
IR ones.Moreover,adetailedcomparisonofthematerialsspectra
(Fig. 2) showssomedifferencesbetweentheCHbandsshapes.