title: Use of luminescent gunshot residues markers in forensic context.
abstract: Chemical evaluation of gunshot residues (GSR) produced by non-toxic lead-free ammunition (NTA) has been a challenge to forensic analyses. Our group developed some luminescent markers specific to the detection of GSR. Here, we evaluated the performance of selected markers in experiments that mimic forensic context and/or routines in which luminescent characteristics would be very useful. We evaluated the influence of markers' addition on the bullet's speed, the rate of shot failure (i.e., when the cartridge case is not fully ejected and/or a new ammunition is not automatically replaced in the gun chamber) as a function of marker percentage, the possibility of collecting luminescent gunshot residue (LGSR) in unconventional locations (e.g. the shooters' nostrils), the LGSR lifetime after hand washing, the transfer of LGSR to objects handled by the shooter, and the dispersion of LGSR at the crime scene and on simulated victims. It was observed that high amounts of marker (10 wt%) cause high rates of failure on pistols, as well as a substantial decrease in bullet speed. However, the use of 2 wt% of marker minimizes these effects and allows LGSR detection, collection and analysis. Moreover, in all conditions tested, markers showed high performance and provided important information for forensic analyses. For instance, the LGSR particles were found on the floor, ranging from 0 to 9.4 m away from the shooter, on the door panel and seats after a car shooting experiment, and were found easily on a pig leg used to simulate a victim. When a selective tagging was done, it was possible to obtain positive or negative correlation between the victim and shooter. Additionally LGSR possesses a fairly long lifetime (9 h) and good resistance to hand washing (up to 16 washes).
authors.affiliation: PGMTR - CCEN, Federal University of Pernambuco-UFPE, Av. Prof. Luiz Freire, S/N, Cidade Universitária, 50740-540 Recife, Brazil; LIMA, Chemistry Institute, University of Brasília-UNB, P.O. Box 04478, 70904-970 Brasília, Brazil. Electronic address: itweber@unb.br.
authors.forename: I T
authors.initials: IT
authors.lastname: Weber
authors.affiliation: PGMTR - CCEN, Federal University of Pernambuco-UFPE, Av. Prof. Luiz Freire, S/N, Cidade Universitária, 50740-540 Recife, Brazil.
authors.forename: A J G
authors.initials: AJ
authors.lastname: Melo
authors.affiliation: PGMTR - CCEN, Federal University of Pernambuco-UFPE, Av. Prof. Luiz Freire, S/N, Cidade Universitária, 50740-540 Recife, Brazil.
authors.forename: M A M
authors.initials: MA
authors.lastname: Lucena
authors.affiliation: LIMA, Chemistry Institute, University of Brasília-UNB, P.O. Box 04478, 70904-970 Brasília, Brazil.
authors.forename: E F
authors.initials: EF
authors.lastname: Consoli
authors.affiliation: LIMA, Chemistry Institute, University of Brasília-UNB, P.O. Box 04478, 70904-970 Brasília, Brazil.
authors.forename: M O
authors.initials: MO
authors.lastname: Rodrigues
authors.affiliation: Fundamental Chemistry Department-DQF, Federal University of Pernambuco-UFPE, Av. Prof. Luiz Freire, S/N, Cidade Universitária, 50740-540 Recife, Brazil.
authors.forename: G F
authors.initials: GF
authors.lastname: de Sá
authors.affiliation: National Institute of Criminalistics, Brazilian Federal Police, SAIS Quadra 07 Lote 23, 70610-200 Brasília, DF, Brazil.
authors.forename: A O
authors.initials: AO
authors.lastname: Maldaner
authors.affiliation: National Institute of Criminalistics, Brazilian Federal Police, SAIS Quadra 07 Lote 23, 70610-200 Brasília, DF, Brazil.
authors.forename: M
authors.initials: M
authors.lastname: Talhavini
authors.affiliation: Fundamental Chemistry Department-DQF, Federal University of Pernambuco-UFPE, Av. Prof. Luiz Freire, S/N, Cidade Universitária, 50740-540 Recife, Brazil.
authors.forename: S
authors.initials: S
authors.lastname: Alves
mesh_terms: D000535:Aluminum / Q000032:analysis; D003020:Clothing; D056831:Coordination Complexes / Q000032:analysis; D003998:Dicarboxylic Acids / Q000032:analysis; D044709:Forensic Ballistics / Q000379:methods*; D006235:Hand Disinfection; D006801:Humans; D049449:Luminescence; D011725:Pyridines / Q000032:analysis; D012867:Skin / Q000737:chemistry; D014466:Ultraviolet Rays; D014948:Wounds, Gunshot; D015032:Zinc / Q000032:analysis
chemical_list: D056831:Coordination Complexes; D003998:Dicarboxylic Acids; D011725:Pyridines; D000535:Aluminum; D015032:Zinc
keywords: Ammunition tagging; Forensic investigation; Gunshot residue; Lead free ammunition; Luminescent marker; Non-toxic ammunition