Martín-Alberca Carlos, Carrascosa Héctor, San Román Itxaso, Bartolomé Luis, García-Ruiz Carmen
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.
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.
Sci Justice. 2018 Jan;58(1):7-16. doi: 10.1016/j.scijus.2017.09.004. Epub 2017 Sep 25.
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.
诸如燃料、酒精和稀释剂等可燃液体可用于犯罪活动，例如纵火。法医专家需要了解它们的化学成分，以及理解不同的改性效果如何影响它们，以便在火灾残骸中正确检测、分类和识别它们。可燃液体的酸蚀变/酸化是一种改性效果，会显著改变化学成分，例如汽油和柴油燃料的化学成分，干扰法医分析和结果解读。然而，迄今为止，关于这种效果对其他相关促进剂的影响的信息很少。在这篇研究论文中，深入研究了硫酸对几种商业稀释剂和其他纵火中可能使用的促进剂的蚀变情况。为此，从纯净样品和酸化样品中获取了光谱（通过衰减全反射傅里叶变换红外光谱法，ATR-FTIR）和色谱（通过气相色谱-质谱联用仪，GC-MS）数据。然后，讨论了每种研究的可燃液体的光谱和色谱变化，提出了几种化学机制来解释产生的新副产物以及初始化合物的逐渐消失。水解、费歇尔酯化和烷基化反应参与了所研究可燃液体的酯、醇、酮和芳香化合物的改性。这些信息对于正确识别这些促进剂可能至关重要。此外，一项探索性分析表明，一些蚀变最严重的可燃液体样品可能彼此非常相似，这可能会对实际案件工作产生影响。
