title: Conjugated polyenes as chemical probes of life signature: use of Raman spectroscopy to differentiate polyenic pigments.
abstract: Polyenes, which are represented by carotenes, carotenoids and conjugated polyenals, are some of the most important targets for astrobiology, because they can provide strong evidence of the presence of organic compounds in the most extreme environments, such as on Mars. Raman spectroscopy has been used as the main analytical tool in the identification of such compounds, for the greatest variety of living species, from microorganisms to animals and plants. However, using only the position of the characteristic Raman bands can lead to errors in tentatively identifying chemicals. In this work, we present a series of observations that can provide a more complete and robust way to analyse the Raman spectrum of a polyenal, in which the position, the intensity, the use of various laser lines for excitation, and the combination of more than one pigment can be considered in the complete analysis.
authors.affiliation: NEEM-Núcleo de Espectroscopia e Estrutura Molecular, Departamento de Química, Universidade Federal de Juiz de Fora, 36036-330, Juiz de Fora, Minas Gerais, Brazil.
authors.forename: Lenize F
authors.initials: LF
authors.lastname: Maia
authors.affiliation: NEEM-Núcleo de Espectroscopia e Estrutura Molecular, Departamento de Química, Universidade Federal de Juiz de Fora, 36036-330, Juiz de Fora, Minas Gerais, Brazil.
authors.forename: Rafaella F
authors.initials: RF
authors.lastname: Fernandes
authors.affiliation: Departamento de Genética, Universidade do Estado do Rio de Janeiro, 20550-000, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Gisele
authors.initials: G
authors.lastname: Lobo-Hajdu
authors.affiliation: NEEM-Núcleo de Espectroscopia e Estrutura Molecular, Departamento de Química, Universidade Federal de Juiz de Fora, 36036-330, Juiz de Fora, Minas Gerais, Brazil luiz.oliveira@ufjf.edu.br.
authors.forename: Luiz F C
authors.initials: LF
authors.lastname: de Oliveira
keywords: Raman spectroscopy; carotenoids; conjugated polyenes; corals; polyenals; sponges