title: Study of Spectral Modifications in Acidified Ignitable Liquids by Attenuated Total Reflection Fourier Transform Infrared Spectroscopy.
abstract: In this work, the spectral characteristics of two types of acidified gasoline and acidified diesel fuel are discussed. Neat and acidified ignitable liquids (ILs) infrared absorption spectra obtained by attenuated total reflection Fourier transform infrared spectroscopy were compared in order to identify the modifications produced by the reaction of the ILs with sulfuric acid. Several bands crucial for gasoline identification were modified, and new bands appeared over the reaction time. In the case of acidified diesel fuel, no significant modifications were observed. Additionally, the neat and acidified ILs spectra were used to perform a principal components analysis in order to confirm objectively the results. The complete discrimination among samples was successfully achieved, including the complete differentiation among gasoline types. Taking into account the results obtained in this work, it is possible to propose spectral fingerprints for the identification of non-burned acidified ILs in forensic investigations related with arson or the use of improvised incendiary devices (IIDs).
authors.affiliation: University Institute of Research in Police Sciences (IUICP), University of Alcalá, Ctra. Alcalá de Henares (Madrid), Spain Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Multipurpose Building of Chemistry, University of Alcalá, Alcalá de Henares (Madrid), Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Martín-Alberca
authors.affiliation: University Institute of Research in Police Sciences (IUICP), University of Alcalá, Ctra. Alcalá de Henares (Madrid), Spain.
authors.forename: Fernando Ernesto Ortega
authors.initials: FE
authors.lastname: Ojeda
authors.affiliation: University Institute of Research in Police Sciences (IUICP), University of Alcalá, Ctra. Alcalá de Henares (Madrid), Spain Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Multipurpose Building of Chemistry, University of Alcalá, Alcalá de Henares (Madrid), Spain carmen.gruiz@uah.es.
authors.forename: Carmen
authors.initials: C
authors.lastname: García-Ruiz
keywords: ATR FT-IR; Acidified ignitable liquid; Attenuated total reflection Fourier transform infrared spectroscopy; Chemical ignition Molotov cocktail; Chemometrics; Fire debris; Gasoline