Aplicação de marcadores químicos fluorescentes em balística forense: avaliação visual e por espectrometria de massas de alta resolução

Abstract

Brazil is a country that suffers from violence these days, mainly due to the uncontrolled use of firearms, favoring trivial crimes. Currently, for ballistic confirmation, trace metals such as antimony and lead are tested by atomic methods such as Inductively Coupled Plasma Atomic Emission (ICP-OES), which is an expensive and time-consuming test. Because of this, it is necessary to identify new ballistic markers in order to speed up the confirmation of the shooter. In this sense, this work sought to evaluate the Brilliant Blue dye (N-ethyl-N-[4-[[4-[ethyl[(3-sulfophenyl)methyl]amino]phenyl](2-sulfophenyl)methylene]-2,5-cyclohexadien-1-ylidene]-3-sulfo-Benzenemetanaminium sodium salt) as a possible ballistic marker in projectiles. Thus, we evaluated it visually, with the aid of UV light, as well as by high-resolution mass spectrometry (HRMS) with electrospray ionization (ESI). For this, the dye was previously characterized by infrared spectroscopy (FTIR), 1H and 13C Nuclear Magnetic Resonance (NMR), and HRMS. Afterwards, a 0.1g portion of the dye was added to .38 caliber revolver ammunition, which was deflated at 5, 10 and 15 meters from the target. Finally, the firing residues were sampled on the shooters' hands and on the targets using swabs soaked in ethyl alcohol, and these samples were subsequently analyzed in the HRMS. The fluorescence of the compound was tested with the aid of a flashlight with UV light emission, on the hands of shooters, targets, deflated cartridges and the gun used in the shooting. As a result, visually it was possible to verify the presence of the dye on the hands and targets and by HRMS. Thus, this work demonstrates that the brilliant blue dye can be used as a chemical marker in ammunition, but more tests are needed to adequate its evaluation. [resumo fornecido pelo autor]