Citation

Martín-Alberca C, Carrascosa H, San Román I, Bartolomé L, Garcia-Ruiz C. Sci. Justice 2018; 58(1): 7-16.

Affiliation

Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Edificio Polivalente de Química, University Institute of Research in Police Sciences (IUICP), 28871 Alcalá de Henares, Madrid, Spain; University of Alcalá, Edificio de Ciencias, Ctra. Madrid-Barcelona Km. 33.6, 28871 Alcalá de Henares, Madrid, Spain.

Copyright

(Copyright © 2018, Forensic Science Society, Publisher Elsevier Publishing)

DOI

10.1016/j.scijus.2017.09.004

PMID

29332697

Abstract

Ignitable liquids such as fuels, alcohols and thinners can be used in criminal activities, for instance arsons. Forensic experts require to know their chemical compositions, as well as to understand how different modification effects could impact them, in order to detect, classify and identify them properly in fire debris. The acid alteration/acidification of ignitable liquids is a modification effect that sharply alters the chemical composition, for example, of gasoline and diesel fuel, interfering in the forensic analysis and result interpretation. However, to date there is little information about the consequences of this effect over other accelerants of interests. In this research paper, the alteration by sulfuric acid of several commercial thinners and other accelerants of potential use in arsons is studied in-depth. For that purpose, spectral (by ATR-FTIR) and chromatographic (by GC-MS) data were obtained from neat and acidified samples. Then, the spectral and chromatographic modifications of each studied ignitable liquid were discussed, proposing several chemical mechanisms that explain the new by-products produced and the gradual disappearance of the initial compounds. Hydrolysis, Fischer esterification and alkylation reactions are involved in the modification of esters, alcohols, ketones and aromatic compounds of the studied ignitable liquids. This information could be crucial for correctly identifying these accelerants. Additionally, an exploratory analysis revealed that some of the most altered ignitable liquid samples might be very similar with each other, which could have impact on casework.

Copyright © 2017 The Chartered Society of Forensic Sciences. Published by Elsevier B.V. All rights reserved.

Language: en

Keywords

Acid alteration; Acidification; Arson; Ignitable liquid; Modification effect; Thinner