Banca de DEFESA: ÍRINAN BARBOSA DE FRANÇA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ÍRINAN BARBOSA DE FRANÇA
DATE: 18/08/2022
TIME: 10:00
LOCAL: Auditório do CCEN
TITLE:

Evaluation of the β-diketonate Eu(btfa)3bipy Complex as a Luminescent Marker of Ammunition for Gunshot Residues Detection.

KEY WORDS:

Chave em Inglês: β-diketonates. lanthanides. Luminescent marker. Gunshot Residues. GSR. Forensic investigation.

PAGES: 93
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

Heavy metal-free or non-toxic ammunition (NTA) was developed to protect the health of public safety agents and the environment. However, the methodologies used to identify the gunshot residues (GSR) of these ammunition have become inefficient. To solve this problem, the implementation of luminescent markers in ammunition was presented as an alternative. These markers are known to allow the visualization of residues at the crime scene using only an ultraviolet lamp, facilitating the visualization, sample collection and subsequent analysis of residues in the laboratory. In addition, they help to clarify the dynamics of the shooting event or even the dynamics of the crime in question. Aiming to expand the ammunition coding process and mainly a possible application in industrial scale, the present work studied the efficiency of the europium β-diketonate complex Eu(btfa)3bipy as a luminescent marker of gunshot residues. This complex was synthesized using a reflux system at 60°C, a simple and easily scalable process for industrial scale. Characterizations by infrared spectroscopy (FTIR) indicated that, in this complex, the europium ion is coordinated to β-diketonate ligands. Through photoluminescence spectroscopy (FL), the emission lines characteristics of the f-f europium transition were observed, and the antenna effect showed be the main mechanism responsible for the excitation of the sample. Thermogravimetric analysis (TGA) showed that the complex is stable up to approximately 300°C. And the Scanning Electron Microscopy (SEM) showed that the complex crystallizes into dense and irregular three-dimensional blocks. After characterization, the complex was evaluated as luminescent marker for GSR. After shots with 9mm conventional ammunition, luminescent residues (LGSR) were visualized on targets positioned at different distances (simulated victims) and on the shooter's hands. It is important to highlighted that the presence of luminescent particles on the hands of a suspect, by itself, is a strong indicator of LGSR. Furthermore, the generated residues were examined using FL and SEM, where it was possible to observe that the emission spectra showed the characteristic transitions of europium, and that the residues also presented a
morphology similar to that of the pure marker. These compositional and morphologic information are essential for the correct identification of a GSR marker. It is important to highlight that the characterization of the LGSR involved non-destructive methods of great interest for forensic investigations, since they are equipment present in the main investigative centers. The results showed that the Eu(btfa)3bipy complex is an efficient luminescent and chemical marker, and its characterization can be applied to forensic routine. 

BANKING MEMBERS:
Presidente - 3218211 - MARCELLA AUXILIADORA DE MELO LUCENA
Interna - 1550600 - INGRID TAVORA WEBER
Externo à Instituição - RODRIGO DA SILVA VIANA - UFAL