title: Raman spectroscopy as a tool for polyunsaturated compound characterization in gastropod and limnic terrestrial shell specimens.
abstract: The colours of mollusc shells were determined using the Raman spectroscopy and these analyses suggest that the conjugated polyenes (carotenoids) and psittacofulvins are the organic pigments incorporated into their skeletal structures responsible by their colorations. The symmetric stretching vibration of the carbonate ion gives rise to a very strong Raman band at ca. 1089 cm(-1) and a weak band at 705 cm(-1), for all samples; the second band characterizes the aragonite as the inorganic matrix and can be used as a marker. The specimens show bands at 1523-1500 and at 1130-1119 cm(-1), assigned to the ν1 and ν2 modes of the polyenic chain vibrations, respectively. Another band at 1293 cm(-1), assigned to the CH=CH in-plane rocking mode of the olefinic hydrogen is also observed in all samples, which reinforces the psittacofulvin compound as the main pigment present in the analyzed samples.
authors.affiliation: NEEM-Núcleo de Espectroscopia e Estrutura Molecular, Departamento de Química, Universidade Federal de Juiz de Fora, Campus Martelos, Juiz de Fora, MG, Brazil.
authors.forename: Leandra N
authors.initials: LN
authors.lastname: de Oliveira
authors.forename: Vanessa E
authors.initials: VE
authors.lastname: de Oliveira
authors.forename: Sthefane
authors.initials: S
authors.lastname: D'ávila
authors.forename: Howell G M
authors.initials: HG
authors.lastname: Edwards
authors.forename: Luiz Fernando C
authors.initials: LF
authors.lastname: de Oliveira
mesh_terms: D060105:Animal Shells / Q000737:chemistry*; D000818:Animals; D002254:Carbonates / Q000032:analysis; D002338:Carotenoids / Q000032:analysis*; D049851:Gastropoda / Q000737:chemistry*; D011090:Polyenes / Q000032:analysis*; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D002254:Carbonates; D011090:Polyenes; D002338:Carotenoids
keywords: Mollusc; Polyenes; Psittacofulvins; Raman spectroscopy