Dissertations / Theses on the topic 'Gunshot residues'

The three introductory chapters are intended to summarise the available knowledge prior to the experimental work and to provide useful background information for chemists, with little or no understanding of firearms, who are required to undertake the chemical aspects of firearms casework examination. Chapter 1 provides a much condensed outline of the historical development of firearms and ammunition, with emphasis on ignition systems up to the development of the percussion primer and self contained ammunition. The second chapter presents a comprehensive literature search on the chemical nature of modem ammunition and firearms, with particular attention to priming compositions and projectiles. The final introductory chapter deals with the nature and properties of firearms discharge residues and outlines the most important developments in the search for a satisfactory detection and identification method. The objective of the experimental work is to record experience gained from the 26 year terrorist campaign in Northern Ireland and to use such experience, coupled with further research and development, to substantially improve existing procedures for firearms and explosives residue detection. The experimental work conducted is detailed in Chapter 4. Chapter 5 deals primarily with the Particle Analysis method for the detection and identification of firearms discharge residue, particular attention being directed towards the particle classification system and discharge residue from mercury fulminate and Sintox primed ammunition. Chapter 6 covers suspect handling procedures and contamination avoidance and makes recommendations for permanent improvements in and regular monitoring of the environment in which suspects are sampled. Chapter 7 outlines the development of a method for the detection of the organic constituents of firearms discharge residues, which is compatible with existing inorganic firearms discharge residue and organic explosive residue detection techniques and which enables all suspects to be routinely screened for inorganic and organic firearms discharge residue and organic explosives residue. The final chapter summanses the conclusions, recommendations and comments arising from the work.

In recent years, Raman spectroscopy has become popular in forensic science. However, most of the work in this area has used laboratory-based, research grade instruments. The aim of this thesis was to establish new methods for forensic Raman analysis which would be suitable for use in laboratories and at crime scenes using commercial portable Raman instruments. Although these systems could potentially enable forensic field analysis, they have been designed with very limited sampling options, typically with very short focal length excitation/collection optics. This makes it difficult to actually use them as intended at crime scenes due to problems locating and focusing on the samples. Here, a new sampling arrangement which involved changing the optical assemblies for excitation/collection and incorporation of a webcam for sample viewing was designed was constructed and tested. This gave a modified system that was actually usable as a handheld device. A new method for analysis of propellant and organic gunshot residue based on a combination of macroscopic observation of particle morphology and Raman spectroscopy for composition analysis was developed. The main obstacle in this work was fluorescence. However, washing with a 95:5 methanol:ethanol mixture removed the fluorescent interference from most propellants so Raman spectroscopy could be used to identify the chemical components of propellants/organic GSR particles and distinguish them from background particles. Raman spectroscopy has also been successfully employed to identify the main pigments/dyes in pen inks and to discriminate between them. Blue gel and liquid ink pens were examined using 633 and 785 nm excitation, it was found that the discrimination given by either of these excitation wavelengths was similar to the combination of both. In addition, the best way to discriminate between the pens was to combine normal Raman measurements on the pigment based inks with SERS on the dye-based systems.

Gunshot residue (GSR) is the term used to describe the particles originating from different parts of the firearm and ammunition during the discharge. A fast and practical field tool to detect the presence of GSR can assist law enforcement in the accurate identification of subjects. A novel field sampling device is presented for the first time for the fast detection and quantitation of volatile organic compounds (VOCs). The capillary microextraction of volatiles (CMV) is a headspace sampling technique that provides fast results (< 2 min. sampling time) and is reported as a versatile and high-efficiency sampling tool. The CMV device can be coupled to a Gas Chromatography-Mass Spectrometry (GC-MS) instrument by installation of a thermal separation probe in the injection port of the GC. An analytical method using the CMV device was developed for the detection of 17 compounds commonly found in polluted environments. The acceptability of the CMV as a field sampling method for the detection of VOCs is demonstrated by following the criteria established by the Environmental Protection Agency (EPA) compendium method TO-17. The CMV device was used, for the first time, for the detection of VOCs on swabs from the hands of shooters, and non-shooters and spent cartridges from different types of ammunition (i.e., pistol, rifle, and shotgun). The proposed method consists in the headspace extraction of VOCs in smokeless powders present in the propellant of ammunition. The sensitivity of this method was demonstrated with method detection limits (MDLs) 4-26 ng for diphenylamine (DPA), nitroglycerine (NG), 2,4-dinitrotoluene (2,4-DNT), and ethyl centralite (EC). In addition, a fast method was developed for the detection of the inorganic components (i.e., Ba, Pb, and Sb) characteristic of GSR presence by Laser Induced Breakdown Spectroscopy (LIBS). Advantages of LIBS include fast analysis (~ 12 seconds per sample) and good sensitivity, with expected MDLs in the range of 0.1-20 ng for target elements. Statistical analysis of the results using both techniques was performed to determine any correlation between the variables analyzed. This work demonstrates that the information collected from the analysis of organic components has the potential to improve the detection of GSR.

Gunshot residue (GSR) mixture consists of partially burned particles of propellant and characteristic particles of elements originating from the primer, bullet, propellant and some additives in the propellant. Since Harrison and Gillory [1] drew forensic scientists’ attention to the fact that GSR contained trace amounts of inorganic compounds such as lead, barium and antimony, a number of analytical techniques have been tested trying to find and establish sensitive, selective and reliable methods to identify and analyse gunshot residues. The standard procedure for the analysis of gunshot residues involves imaging these small metallic particles using scanning electron microscopy (SEM) and subsequent compositional analysis using Energy Dispersive X-ray Analysis (EDX). This study focuses on the analysis organic compounds in GSR. It is motivated by the increasing need to overcome the problems with the analysis of lead-free ammunitions. A comprehensive literature review was performed in order to determine the most commonly encountered organic compounds in GSR. These compounds include diphenylamine, methylcentralite, ethylcentralite, nitroglycerine, 2-nitrodiphenylamine and 4-nitrodiphenylamine. It has been clearly demonstrated using standard materials and appropriate calibration curves that gas chromatograph and mass spectrometry (GC/MS) is capable of providing limits of detection that are consistent with the concentrations of the key organic constituents found in gunshot residues. Furthermore, we have demonstrated that the relative concentrations of seven key components can be used to provide branding information on the shotgun cartridges. A strong relationship was found between the chemical composition of fired and unfired powder. Therefore, it is possible to differentiate between two ammunition brands through the analysis of the organic constituents. Traditional fingerprint powders such as titanium dioxide, aluminium, carbon black, iron oxide, lycopodium spores and rosin are used to enhance fingerprint left at the scene of crime. More recently nanoparticles have been demonstrated to be highly effective for the enhancement of the fingerprints [2]. Silica nano-particulates of defined size and shape were synthesised and functionalised with two different functional groups (phenyl and long chain hydrocarbon) using a Tri- phasic Reverse Emulsion (TPRE) method. These nano-particulates were characterised using scan electron microscope (SEM), transmission electron microscopy (TEM), elemental analysis, particles size analyser, BET surface area and solid-state nuclear magnetic resonance (NMR) spectroscopy. These powders were used as an effective agent to visualise latent fingerprints on different surfaces. Furthermore, they have been utilised to absorb any organic materials within the fingerprint from the discharged of weapon. Analyses of the adsorbed organic residues were performed using GC/MS and Raman spectroscopy. The results showed that the synthesised silica nano-particulate fingerprint powder gave better result in term of their ability to absorb organic materials in GSR and enhance the visualisation of the latent fingerprint compared to a single commercial powder.

A ciência forense moderna caminha lado a lado com a pesquisa científica. Os cientistas forenses se deparam diariamente com vários casos que requerem a análise de resíduos provenientes de disparos de arma de fogo (gunshot residues - GSR). Este trabalho contempla o desenvolvimento de uma metodologia para determinar assinaturas químicas de disparos de arma de fogo, medindo-se as concentrações de Pb, Ba e Sb presentes nos resíduos provenientes destes disparos depositados nas proximidades do orifício de entrada de projéteis, baseada na técnica de espectrometria de massas de alta resolução com fonte de plasma indutivamente acoplado (ICP-MS). Foram realizados disparos em cinco tipos de tecidos-alvos e coletados testemunhos em regiões próximas ao orifício de entrada dos projéteis. Os resultados demonstraram que o método possibilitou identificar e distinguir os resíduos de revólver calibre .38 ao de pistolas calibres .40 e 9 mm. O uso de gráficos ternários como ferramenta de análise dos dados coletados, permitiu identificar padrões específicos de distribuição de amostras em branco e dos resíduos depositados após disparos de revólveres e pistolas. A metodologia possibilitou a atribuição da origem dos disparos por meio de confirmação dos resíduos coletados também das mãos dos atiradores. Como conseqüência a metodologia representa um grande avanço nos procedimentos da polícia e visa adicionar uma contribuição valiosa às investigações forenses.
The modern forensic science goes hand in hand with scientific research. The forensic scientists are faced every day with many cases requiring the analysis of residues from firing gun (gunshot residues GSR). This works describes the development of a methodology to determine chemical signatures of shots from a firearm, by measuring the concentrations of Pb, Ba e Sb in the residues from these shots deposited near the entrance hole of bullets, based on the technique with high resolution inductively coupled plasma mass spectrometry (HRICP-MS). Shots were performed on five types of target-fabrics and collected testimonies from regions close to the entrance hole of projectiles. The results showed that the method enabled us to identify and distinguish the residues of the .38 caliber revolver and pistols .40 and 9mm caliber. The use of ternary graphs as a tool for data analysis helped to identify specific patterns of distribution of blank samples and gunshot residues deposited after firing revolvers and pistols. The methodology enabled the assignment of the origin of the shot through the confirmation of the residues collected also from the hands of shooters. As a result the methodology in police procedures and aims to add a valuable contribution to forensic investigations.

Diariamente milhares de profissionais da área de segurança utilizam armas de fogo, quer em ações de combate a criminalidade; quer em treinamentos obrigatórios que a atividade exige. Apesar disso a quantidade de informação sobre os riscos à saúde desses profissionais devido da exposição aos resíduos de disparos, especialmente quando são usadas armas de grosso calibre, ainda é escassa. Este trabalho pretendeu trazer uma contribuição às discussões sobre o tema com uma proposta de normalização para ser observada no planejamento dos procedimentos de treinamento e atividades desses profissionais. Para tanto foram estudados dois grupos de profissionais: o primeiro, profissionais militares da Polícia Militar do Estado de São Paulo durante intensas jornadas de treinamento com esforço físico e grande numero de disparos com armas de fogo de grosso calibre O segundo grupo envolvendo peritos criminais do núcleo de balística do Instituto de Criminalística da Secretaria de Segurança do Estado de São Paulo. Foram utilizadas amostras de materiais biológicos (sangue, urina e saliva) e amostras do ar dos ambientes fechados onde estas rotinas de trabalho ocorrem. No caso dos profissionais militares, os níveis dos metais monitorados no ar variaram de acordo com o tipo de arma e munição utilizada, sendo ultrapassado o limite de tolerância estabelecido na NR-15 (100 μg/m3) após o uso de espingarda (216 μg/m3). A média e desvio padrão dos níveis de chumbo no sangue antes (3,3 μg/dL ± 0,7) e depois (18,2 μg/dL ± 5,1) do curso indicam que ouve um aumento importante num curto período de tempo, também houve aumento nos níveis de chumbo e antimônio na urina. No segundo caso de exposição ocupacional aos resíduos de disparo no núcleo dos peritos balísticos se verificou uma baixa quantidade de resíduos no ambiente de trabalho, se comparado com o Limite de Tolerância preconizado na norma NR-15, e uma baixa quantidade de chumbo no sangue (3,9 μg/dL ± 0,8) se comparado com o Índice Biológico Maximo Permitido IBMP (60 μg/dL) estabelecido na NR-7, sem embargo quando comparado o grupo de balísticos com o grupo controle (1,8 μg/dL ± 0,7) estabeleceu se uma diferença. O estudo dos cenários de exposição permitiu gerar uma proposta para trabalho seguro nestes ambientes e recomendações para o desenho e uso de estantes fechados de disparo. Os câmbios que se introduzam nos costumes e comportamentos dos profissionais levaram uma diminuição do risco associado ao uso de armas de fogo nestes estantes. As conclusões do presente trabalho contribuem para a adequação das medidas de proteção dos trabalhadores de segurança, e na adequação da legislação relativa aos limites de tolerância e índices bilógicos empregados no controle de saúde ocupacional.
Daily thousands of military officers from security forces use fire arms, sometimes in actions against crime or in mandatory training seasons. Despite of this, there is a few information about the risk associated with firing ranges, especially when heavy weapons are used in a hard training seasons with hard physical work and elevated number of rounds, the security forces might be under risk of intoxication. Other types of exposure with less frequency and intensity, but using a high lead containing ammunition and different types of weapons, like in the ballistics forensic cases are not yet sufficiently studied. Data from these types of occupational exposure in these environments are important in order to establish safety working procedures. The goal in this research is to study the occupational exposure in the police department and the ballistics laboratories in personal who are under the risk of this exposure in their routinely daily work and during the training courses in the Sao Paulo´s Military Police Department. In order to reach this, some biological materials were sampled (blood, urine and saliva) as well as air samples from the environment in the firing ranges during routinely daily work. In the two studied cases the monitored airborne lead varied in accordance with the type of weapon and ammunition used, and was ultra passed the limit of exposure established in the norm NR-15 (100 μg/m3) after the shot gun was used during the training season (216 μg/m3). The average and standard deviation of lead content in blood before (3,3 μg/dL ± 0,7) and after (18,2 μg/dL ± 5,1) de training season shows a significant rise of the lead levels in a very short period of time. An increment of the lead and antimony levels in urine was demonstrated. The other studied case, in the ballistics laboratory showed minor increments of lead in blood and airborne residues when compared with the limits established in the norm NR- 7 (60 μg/dL) but when compared in a cohort study the data lead to establish a significant difference between the exposed group from the ballistics and the control group. These results let us to design a proposal to safely work in these environments and to give the recommendations in the engineering design of the indoor ranges. The implemented changes will lead to minimize the risk associated with the use of weapons and lead containing ammunitions. The conclusions of the present work contribute to adequateness of the related legislation and the tolerance limits of exposure used in the occupational health practice.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Este trabalho descreve o desenvolvimento de métodos analíticos para a determinação quantitativa de furosemida e bumetanida em amostras de urina utilizando espectroscopia por reflectância difusa (para a furosemida) e por imagem por scanner com quantificação através do histograma de cores utilizando o padrão RGB (para ambas). Envolve também o desenvolvimento de um método quantitativo para a detecção de chumbo em resíduos de armas de fogo (GSR) nas mãos de atiradores utilizando membranas de celulose bacteriana como substrato de coleta, visando o descobrimento do tempo de disparo. Também foi realizada a quantificação de chumbo em amostras de tintura para cabelos utilizando método previamente desenvolvido, visando detecção da adulteração destes produtos e controle de qualidade. Estuda também a potencialidade do uso das membranas de celulose bacteriana para a coleta de impressões digitais. Os métodos desenvolvidos consistem na reação da furosemida (FUR) com o regente cromogênico paradimetilaminocinamaldeído (p-DAC) 0,70% e ácido clorídrico (HCl) 1,72 mol L-1 em papel de filtro qualitativo com barreiras hidrofóbicas, com detecção espectrofotométrica e por histograma de cores; na reação do íon chumbo(II) (Pb2+) com rodizonato de sódio (ROD) 0,16% em meio micelar de dodecil sulfato de sódio (SDS) 5 mmol L-1 em membranas de celulose bacterianas, com detecção espectrofotométrica e por microscopia eletrônica de varredura (MEV); na reação de bumetanida (BMT) com o reagente p-DAC 0,6% e HCl 0,26 mol L-1 em papel de filtro qualitativo com barreiras hidrofóbicas, com detecção por histograma de cores e na coleta de impressões digitais utilizando membrana de celulose bacteriana impregnadas com ninidrina, nitrato de prata ou óxido de zinco, dos quais o nitrato de prata e a ninidrina atuaram como agentes de coleta razoáveis. Todas as concentrações foram otimizadas por planejamentos quimiométricos. As reações foram realizadas na forma de spot test, envolvendo a formação de um produto colorido em 545 nm para o chumbo, em 585 nm para a furosemida e 520 nm para a bumetanida. As curvas analíticas foram contruídas a partir de soluções padrões dos respectivos analitos. Os métodos desenvolvidos para a bumetanida e para a furosemida foram aplicados em amostras de urina sintética e natural fortificadas e os resultados obtidos foram comparados estatisticamente com métodos comparativos. A validação dos métodos foi realizada por adição de padrão e recuperação e por comparação de métodos, no caso da FUR e da BMT, obtendo-se recuperações entre 98,0 e 115,3% para os métodos de quantificação da furosemida e entre 93,0 e 102,0% para o método de quantificação da bumetanida. O método de coleta de GSR é baseado na utilização de membranas finas de celulose bacteriana desenvolvidas pelo Grupo de Materiais Fotônicos do IQ-UNESP.Para os GSR foram realizadas 40 coletas totais em tempos de coleta após o disparo (diferentes e conhecidos), sendo sua comparação realizada através das curvas analíticas, mostrando ser possível a detecção do tempo de disparo com uma margem de erro de aproximadamente 5 minutos. Os resultados foram comparados estatisticamente e os valores obtidos a partir de testes estatísticos mostraram que os métodos podem ser usados para análises de rotina em laboratórios forenses.
This work describes the development of analytical methods for the quantitative determination of furosemide and bumetanide in urine samples using diffuse reflectance spectroscopy (for furosemide) and scanning imaging with quantification by color histogram using RGB color pattern (for both). It involves also the development of a quantitative method for the detection of lead in gunshot residues (GSR) in the hands of the shooters using bacterial cellulose membranes as substrate collection, aiming the discovery of shooting time. It is also done the quantification of lead in progressive hair lotions samples using a previously developed method, aiming the detection of products adulterations and quality control. It also studies the potentiality of the usage of bacterial cellulose membranes for the collection of fingerprints. The developed methods are consisted in the reaction of furosemide (FUR) with the cromogenic reagent p-dimethylamino cinnamaldehyde (p-DAC) 0.70% and hydrochloric acid (HCl) 1.72 mol L-1 in qualitative filter papers with hydrophobic barrier, with spectrophotometric detection and by color histogram; in the reaction of lead(II) ion (Pb2+) with sodium rhodizonate (ROD) 0.16% in micellar medium of sodium dodecyl sulfate (SDS) 5 mmol L-1 in bacterial cellulose membranes with spectrophotometric detection and by scanning electron microscopy; in the reaction of bumetanide (BMT) with the reagent p-dimethylamino cinnamaldehyde (p-DAC) 0.6% and hydrochloric acid (HCl) 0.27 mol L-1 in qualitative filter papers with hydrophobic barrier with color histogram detection an in the collect of fingerprints using bacterial cellulose membranes impregnated with ninhydrine, silver nitrate or zinc oxide, of which the silver nitrate and ninhydrin acted as reasonable collection agents. All concentrations were optimized through chemometrics designs. The reactions were carried out as spot test, involving the formation of a colored product at 545 nm for lead, in 585 nm for furosemide and in 520 nm for bumetanide. Analytical curves were built from standard solutions of the respective analytes. The methods developed for furosemide and bumetanide were applied in fortified synthetic and natural urine samples and the results obtained were compared statistically with comparative methods. The validation of the methods were performed by standard addition and recovery and by comparison of methods, for FUR and BMT, yielding recoveries between 98.0 and 115.3% for furosemide quantification methods and between 93.0 and 102.0% for the quantification method for bumetanide. GSR collection method is based on the use of thin membranes of bacterial cellulose developed by Photonic Materials Group IQ-UNESP. For GSR, 40 total collections were carried out in known and different times of collection after shooting times and their comparison through analytical curves were done, showing the possibility of the detection of the shooting time with an error of 5 minutes, approximately. The results were statistically compared and the values obtained from statistical tests showed that the methods can be used for routine analysis in forensic laboratories.

Gunshot residue (GSR) is a complex chemical mixture that is created during the discharge of a firearm. Its detection and interpretation play a crucial role in the investigation of firearm incidents. Current GSR analysis is limited to inorganic GSR (IGSR), however, the evidential value could be strengthened by inclusion of organic GSR (OGSR). The present study aims to address this potential by proposing a categorisation system for relevant OGSR compounds and developing a methodology for the collection, extraction and analysis of both organic and inorganic GSR from a single sample. The organic composition of more than 50 propellant powders has been determined and compared against more than 200 propellant compositions reported in the literature. This work has resulted in a three-tier categorisation system for OGSR compounds, which together with the current IGSR classification will provide unequivocal identification of GSR materials with the possibility of discriminating between GSR from different ammunition types. Evaluation of MonoTrap extraction showed that this is an effective pre-concentration technique for the characterisation of propellants. Solid-phase microextraction (SPME), however, was the superior method for the extraction of OGSR compounds from various sampling media, including swabs and stubs. The optimised methodology involves GSR collection using carbon adhesive stubs followed by SPME gas chromatography – mass spectrometry (GC-MS) analysis of OGSR and subsequent scanning electron microscopy – energy-dispersive X-ray spectrometry (SEM-EDX) analysis for IGSR. This protocol has resulted in the detection of both characteristic IGSR and categorised organic compounds, demonstrating the ability to obtain a full chemical profile from a single sample. Detection of both first and second tier organic compounds provides complementary compositional information that could be used to discriminate between samples. Furthermore, this methodology requires no changes to the current sampling and IGSR analysis protocols and addresses the limited storage time of OGSR. Since GC-MS instruments are readily available in most analytical laboratories, implementation of the proposed protocol is feasible.

This thesis investigates the feasibility of using ion beam analysis (IBA) techniques for the characterisation of gunshot residue (GSR) in forensic casework. GSR-is an important type of trace evidence used to link suspects to shooting incidents. The current forensic procedure for GSR analysis utilises scanning electron microscopy with energy dispersive X -ray spectroscopy (SEM-EDS), but this lacks sensitivity to important trace elements when compared with IBA. In this thesis, the development of a new protocol for GSR analysis by IBA is described, including a robust particle relocation method, an efficient spectral fitting process and the implementation of a background subtraction procedure. Canonical discriminant function analysis (CDP A) is employed to demonstrate the ability of IBA to discriminate between different brands of ammunition in a way not currently possible using existing GSR casework methodologies. A database of results for GSR particles collected from cartridge cases and hands is presented along with a discussion as to how it would be best utilised in a casework scenario. An investigation into how IBA can be applied to lead-free ammunitions is also presented. These ammunitions are known to produce particles that are problematic for forensic examiners to positively identify as being GSR. IBA is shown to increase the evidential value of such particles due to the higher sensitivity of IBA when compared with SEM-EDS. IBA is shown to offer improved discrimination between all types of ammunition using methods that would not require any alteration to well- established sample collection and preparation procedures.

Duas metodologias distintas foram desenvolvidas para a determinação de chumbo em Resíduos de Disparos de Armas de Fogo (RDAF) utilizando microeletrodo de ouro. Na primeira delas, a superfície eletródica foi modificada com filme de bismuto em meio alcalino (pH = 13) e na outra as análises foram realizadas com microeletrodo não modificado em meio ácido com cloreto. Os RDAF foram coletados do alvo atingido pela bala e das mãos do atirador. Dos alvos, foi recortada uma região próxima ao orifício feito pela bala. Já para remoção dos RDAF das mãos do atirador, foi utilizado um algodão embebido em solução de EDTA 2% (m/v). Os resíduos foram submetidos a um processo de extração que consistiu em adicionar 10 mL de solução de HNO3 10% (m/m) ao frasco contendo o alvo ou o algodão com os RDAF. Em seguida, a mistura foi submetida ao ultrassom por 2 horas a uma temperatura de 60°C. As amostras provenientes dos alvos foram analisadas com o microeletrodo de ouro modificado com bismuto em meio alcalino por voltametria de redissolução anódica. Com essa metodologia, obteve-se um limite de detecção (3σ/sensibilidade) de 12,5 nmol L-1, uma faixa linear entre 40 e 6700 nmol L-1 e um desvio padrão relativo de 3,4% (n = 12). Foi possível analisar amostras provenientes de duas armas diferentes (pistola 9 mm e revólver 0.38 polegadas) e três munições distintas (normal, spl® e CleanRange®). Constatou-se um aumento da quantidade de chumbo presente nos resíduos à medida que o atirador se aproxima do alvo e que os valores dependem da arma e munição utilizadas. Com a outra metodologia as análises foram realizadas na própria solução extratora, com adição de cloreto, sem qualquer modificação da superfície eletródica. Neste caso, o limite de detecção (3σ/sensibilidade) encontrado foi de 1,7 nmol L-1, a faixa linear ficou entre 10 e 100 nmol L-1 e o desvio padrão relativo de 10 medidas foi 2,5%. Foram analisados resíduos provenientes das mãos dos atiradores de quatro diferentes armas (revólver 0.38 polegadas, espingardas calibre 12, 22 e 38) e de seis diferentes munições (CleanRange®, normal, semi-enjaquetada, 3T®, Eley® e CBC®). Os resultados obtidos com a metodologia proposta foram comparados com aqueles oriundos de análise por espectroscopia de absorção atômica e houve concordância em um nível de confiança de 95%. Foi também realizada uma análise quimiométrica das soluções contendo os RDAF. Os resultados mostraram a possibilidade de discriminação em relação à arma e munição utilizadas. Os filmes formados nas superfícies eletródicas foram estudados utilizando o Microscópio Eletroquímico de Varredura (SECM), a Microbalança Eletroquímica de Cristal de Quartzo (MECQ) e o Microscópio Eletrônico de Varredura (MEV). A deposição dos filmes de bismuto, chumbo e bismuto/chumbo em meio alcalino ocorre de forma heterogênea e esses filmes reagem com oxigênio e ferricianeto. Em meio ácido, a presença do cloreto na solução de depósito do filme de chumbo provoca aumento na rugosidade do filme, com consequente melhoria no sinal analítico. Também se observou que o cloreto facilita o processo de redissolução do filme de chumbo.
Two different methodologies were developed to analyze lead from gunshot residues (GSR) with a gold microelectrode: modification of the electrode surface with a bismuth film in alkaline solution (pH = 13) and use of an unmodified gold microelectrode in acidic media with chloride. GSR were collected from cloth targets and shooters\' hand after test firing. From the targets, a region close to the bullet hole was cutted off. GSR were removed from the shooters\' hand using a cotton swab embedded in a 2% (m/v) EDTA solution. The target and the cotton swab were placed in a steril vial containing 10 mL of a 10% (m/m) HNO3 solution to extract the GSR. Then, all vials were placed in the ultrasound for 2 hours at 60°C. Samples from the targets were analyzed with a gold microelectrode modified with a bismuth film in alkaline solution by anodic stripping voltammetry with a detection limit of 12.5 nmol L-1 (3σ/slope), linear range between 40 and 6700 nmol L-1 and a relative standard deviation of 3.4% (n = 12). Two different handguns (pistoll 9 mm and a revolver 0.38 inches) and tree different ammunition (normal, spl® and CleanRange®) were analyzed and the lead amount was dependent on the gun and ammunition used in the tests. An increase in the amount of lead from the GSR was observed as the distance between the shooter and the target decreased. Lead analyses were also performed in the extraction solution with bare gold microelectrodes in the presence of chloride ions. In this case, the detection limit was 1.7 nmol L-1 (3σ/slope), the linear range lied between 10 and 100 nmol L-1 and the relative standard deviation for 10 measurements was 2.5%. GSR residues form four different guns (revolver 0.38 inches, 12 caliber pump, a repeating rifle 0.38 and a semi automatic .22 caliber rifle) and six different ammunitions (CleanRange®, normal, semi jacketed, 3T®, Eley® and CBC®) were analyzed. The results obtained with the proposed methodology were compared with those from atomic absorption spectroscopy analysis and the paired t-test student indicated that there was no significant difference between the results obtained with both methods at a 95% confidence level. A chemometric analysis was also performed and the results showed the possibility to discriminate the guns and the ammunitions used. Metallic flms formed onto the electrode surface were studied by using Scanning Electrochemial Microscopy (SECM), Electrochemical Quartz Crystal Microbalance (EQCM) and Scanning Electronic Microscopy (SEM). The deposition of bismuth, lead and bismuth/lead films in alkaline solution is heterogeneous and the films react with oxygen and ferricyanide. In acidic media, the presence of chloride ions in the depositing solution causes an increase in the film roughness and facilitates the lead film dissolution

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Considerando o grande aumento das mortes violentas, principalmente no Brasil, e a crescente utilização de armas de fogo para cometer tais crimes, a balística forense associada a entomologia forense se tornam grandes aliadas nas investigações criminais. As concentrações de chumbo (Pb), bário (Ba) e antimônio (Sb), caracerísticos de resíduos de disparo de arma de fogo (GSR GunShot Residue), foram monitoradas em larvas de moscas (imaturos de Chrysomya albiceps). As coletas sucederam em um cadáver de porco, do sexo feminino, morto com três disparos realizados com pistola Taurus®, calibre .40 a curta distância (entre 25 e 40 cm), sendo dois disparos na região cefálica e um na região abdominal, em um período de 2 a 12 dias após a morte, durante o inverno, sob a influência da chuva e alta umidade relativa do ar. Dessa forma, o objetivo deste trabalho foi avaliar a aplicabilidade da técnica de espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES) para a quantificação de Pb, Ba e Sb proveniente de GSR em larvas cadavéricas num ambiente não controlado, simulando um caso real de homicidio. Foi possível detectar e quantificar os três elementos traço de interesse pela técnica proposta, onde as concentrações mantiveram-se praticamente constante durante o estágio de putrefação. Concentrações mínimas (Pb = 382,26 μg·L-1; Ba = 140,50 μg·L-1; Sb = 39,18 μg·L-1) e as concentrações máximas (Pb = 522,66 μg·L-1; Ba = 190,30 μg·L-1; Sb = 56,14 μg·L-1) foram encontradas durante o terceiro e quinto dia post mortem, respectivamente. As amostras também foram analisadas pelo teste colorimétrico usando rodizonato de sódio (reação Feigl-Suter) apresentando resultado negativo para todas as soluções obtidas a partir dos imaturos de Chrysomya albiceps. Uma hipótese para a constância nas concentrações dos três elementos, é que de acordo com a literatura, as larvas da espécie Chrysomya albiceps podem exercer papel como predadora intraguilda de larvas de outras espécies de Dípteras, além de realizar canibalismo. Sendo assim, a técnica de ICP OES apresenta maior sensibilidade na quantificação frente ao convencional teste colorimétrico, mostrando ser uma técnica aplicável a esse tipo de matriz. É importante notar que o desenvolvimento tal pesquisa é de grande importância forense e é uma técnica que apresenta potencial para aplicação futura em casos de morte violenta, em que a vítima se encontra em decomposição inicial, moderada e avançada. Nesse aspecto, o desenvolvimento e aperfeiçoamento de metodologias eficientes são de grande relevância para a elucidação de crimes.

The determination of how far a firearm was from a victim or target when it was discharged is a frequent request to crime laboratories. This determination requires test firing the firearm at various distances to compare gunshot residue patterns made during the test with patterns on the victim or target. Crime laboratories stipulate that the same firearm and ammunition used in commission of the crime must be used for this testing; however, little empirical evidence exists supporting this requirement. It was the purpose of this study to determine if there were any significant differences using different firearms and different ammunition in distance determination testing. The findings indicated that no significant differences occurred with different firearms but there were significant differences with different brands of ammunition.

This dissertation will focus on the extraction of volatile organic compounds associated with gunshot residue from articles of clothing, followed by analysis with mass spectrometry. During the discharge of a weapon, a cloud of volatile organic gunshot residue (OGSR) is dispersed around a firearm. This will create a high probability of transfer between the OGSR and the clothing of individuals who are near a discharged weapon. The first part of this dissertation will be the development of a method for removal of volatile OGSR from articles of clothing. Extraction of OGSR will be completed by solid phase microextraction (SPME), followed by separation and analysis by gas chromatography-mass spectrometry (GC/MS). Many parameters will require optimization for proper extraction of OGSR from articles of clothing. Following development of a SPME procedure, figures of merit were determined such as linearity and limits of detection/quantification, obtaining levels of detection of 0.206 ng/cm2 on a 100 cm2 cotton cloth. Applications of this extraction method were investigated including the determination of the distance OGSR travels from a discharged weapon and the extraction of OGSR with different clothing materials by SPME. The second part of this dissertation will focus on the development of an on-line solvent extraction method for removal of OGSR from articles of clothing, followed by analysis with paper spray mass spectrometry. Issues using SPME of certain types of clothing materials required the development of an alternative method for removal of OGSR from articles of clothing. Use of an on-line solvent extraction technique of OGSR from articles of clothing followed by analysis with paper spray mass spectrometry allowed for detection of OGSR at comparable levels to a headspace SPME procedure. Use of paper spray with an ion trap mass spectrometer permitted the soft ionization of OGSR compounds followed by tandem mass spectrometry to obtain structural information. Extraction of OGSR from articles of clothing has potential to determine if an individual was present during the discharge of a firearm. Extraction of OGSR from articles of clothing will provide an alternative to traditional methods of gunshot residue analysis currently in use.

In many cases of crimes involving a firearm, police investigators need to know how far the firearm was held from the victim when it was discharged. Knowing this distance, vital questions regarding the re-construction of the crime scene can be known. Often, the original firearm used in commission of a suspected crime is not available for testing or is damaged. Crime laboratories require the original firearm in order to conduct distance determination tests. However, no empirical research has ever been conducted to determine if same make and model firearms produce different results in distance determination testing. It was the purpose of this study to determine if there are significant differences between the same make and model of firearms in distance determination testing. The findings indicate no significant differences; furthermore they imply that if the original firearm is not available, another firearm of the same make and model may be used.

The capillary microextraction of volatiles (CMV) device was equipped with a novel Peltier cooler to investigate cryofocused extraction of organic gunshot residue (OGSR) for the first time. Prior research demonstrated the CMV’s capabilities for detecting nitroglycerin, 2,4-dinitrotoluene, diphenylamine, and ethyl centralite on shooters’ hands via gas chromatography-mass spectrometry. Further method development increased the recoveries of these four target compounds with an optimal 20-minute equilibrium time at 80˚C followed by extracting 3 L at a 1 L/min flow rate. The Cryo-CMV was evaluated for detection of semi-volatile OGSR compounds. The unique challenges presented with sampling of semi-volatiles were overcome by sample heating, applying high (>1 L/min) sampling flow rates and heating the transfer line between the container and cooled CMV. Cryofocusing at -10˚C provided increased recoveries for smokeless powders and OGSR compounds and therefore demonstrates excellent potential for other forensic applications with analysis of VOCs from fire debris and illicit drugs.

The goal of this project was to develop a rapid separation and detection method for analyzing organic compounds in smokeless powders and then test its applicability on gunshot residue (GSR) samples. In this project, a total of 20 common smokeless powder additives and their decomposition products were separated by ultra performance liquid chromatography (UPLC) and confirmed by tandem mass spectrometry (MS/MS) using multiple reaction monitoring mode (MRM). Some of the targeted compounds included diphenylamines, centralites, nitrotoluenes, nitroglycerin, and various phthalates. The compounds were ionized in the MS source using simultaneous positive and negative electrospray ionization (ESI) with negative atmospheric pressure chemical ionization (APCI) in order to detect all compounds in a single analysis. The developed UPLC/MS/MS method was applied to commercially available smokeless powders and gunshot residue samples recovered from the hands of shooters, spent cartridges, and smokeless powder retrieved from unfired cartridges. Distinct compositions were identified for smokeless powders from different manufacturers and from separate manufacturing lots. The procedure also produced specific chemical profiles when tested on gunshot residues from different manufacturers. Overall, this thesis represents the development of a rapid and reproducible procedure capable of simultaneously detecting the widest possible range of components present in organic gunshot residue.

Improvised explosives may be based on smokeless gunpowder, fertilizers, or inorganic oxidizers such as nitrate (NO3-), chlorate (ClO3-), and perchlorate (ClO4-) salts. Identification is a priority for the military and law enforcement but due to their varying physical properties and complexity, identification can be challenging. Consequently, three methods have been developed to aid in presumptive and confirmatory detection. Smokeless powder contains plasticizers, stabilizers, dyes, opacifiers, flash suppressants, and other compounds. Identification of these additives can narrow down or identify the brands of smokeless powder used in a device. Fourteen organic smokeless powder components were identified by capillary electrochromatography (CEC) using a hexyl acrylate monolithic stationary phase coupled to UV detection and time-of-flight mass spectrometry (TOF-MS). The CEC-UV method efficiently detects all 14 organic components, while TOF-MS provides sensitivity and selectivity. A mixed smokeless powder component standard was analyzed and the composition of the additive package in commercial smokeless powders determined. Detection limits ranged from 1.0 – 3.2 μg/ml and analysis time was 18 minutes. Second, a procedure for the detection of urea nitrate (UN) and ammonium nitrate (AN) by infusion electrospray ionization - mass spectrometry (ESI-MS/MS) was developed. Solubility tests were performed to find a solvent for both UN and AN that did not cause UN to dissociate. Two adduct ions were detected for each explosive: for AN, m/z 178 [2AN+NH4]+ and m/z 258 [3AN+NH4]+ ions, and for UN m/z 185 [UN+NO3]− and m/z 248 [UN+HNO3+NO3]−. Specificity of the analysis was examined by mixing the explosives with various salts and interferents. Gas-phase adduct ions were useful in distinguishing between ion pairs and mixed salts. Finally, a paper microfluidic device (PMD) was developed as a presumptive test using colorimetric reagents for the detection of ions associated with improvised explosives. The device was configured to test for nitrate (NO3-), nitrite (NO2-), chlorate (ClO3-), perchlorate (ClO4-), and urea nitrate (UN). Proof of concept was performed using extracts of soil containing inorganic oxidizers. The development of these analytical methods allows the detection of smokeless powder components, fertilizers, and oxidizers and expands the suite of analytical methods available for the analysis of improvised explosives.

Gunshot residue (GSR) is produced during a firearm discharge and its recovery from the hands of a suspect may be used to support an inference that the suspect discharged a firearm. Various mechanisms of GSR transfer and deposition involving the hands of subjects were studied through a series of experimental scenarios that were intended to mimic real-world forensic situations. Samples were analysed using SEM-EDX with an automated search and detection package (INCAGSR, Oxford Instruments, U.K.). The results demonstrate the possibility of recovering considerable quantities of GSR from the hands of subjects as a result of a secondary transfer via a handshake with a shooter, or through handling a recently discharged firearm. As many as 129 particles were recovered from a handshake recipient. Additionally, GSR particles were found to undergo tertiary transfer following successive handshakes, while the possibility of GSR deposition on the hands of a bystander was confirmed. Particle size analysis revealed that very large (>50µm and >100µm) particles may undergo secondary transfer. The implications of these findings for forensic investigations are considered, particularly for interpreting the presence of GSR under competing activity level propositions about its deposition and the actions of the suspect. Bayesian Networks are inferential tools that are increasingly being employed in the interpretation of forensic evidence. Using the empirical data derived during the experimentation, the utility of Bayesian Networks for reasoning about mechanisms of GSR deposition is demonstrated. Further research aimed at unlocking the interpretative potential of GSR through empirical research and establishing the use of Bayesian Networks in forensic applications is recommended. It is anticipated that this emphasis on empirical support and probabilistic interpretation, in combination with the findings of this study, will strengthen the scientific basis of inferences made about GSR evidence and contribute to the accurate interpretation of evidence in legal settings.

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CAPES
Resíduos de tiro (GSR) são evidências físicas de grande valor forense em casos envolvendo o uso de armas de fogo. Mas apesar de sua importância, existe uma carência metodológica para a caracterização do GSR proveniente de munição ambiental (NTA). Adicionalmente, o tamanho micrométrico das partículas geradas torna sua detecção em uma cena de crime ou em um suspeito uma tarefa difícil, podendo originar falsos-negativos. Neste sentido, tem sido proposto o uso de materiais luminescentes para a marcação química e óptica de munições. O presente trabalho aborda o desenvolvimento de marcadores luminescentes baseados na rede metal-orgânica (MOF) [Ln(BTC)] (em que BTC = ácido trimésico), desde a sua síntese, aplicação e avaliação da toxicidade, assim como seu uso na codificação de munição e sua caracterização junto aos resíduos orgânicos de disparo (OGSR). Por isto, este trabalho é dividido em cinco capítulos. No primeiro são discutidos aspectos relativos à síntese da MOF [Eu(BTC)] e à sua influência nas propriedades estruturais, térmicas e espectroscópicas dessa rede. Para tal, os métodos de síntese hidrotermal convencional e hidrotermal assistido por micro-ondas (MW), com diferentes tempos de síntese e proporções metal:ligante, são analisados. Com os métodos adotados, a MOF [Eu(BTC)] foi obtida com elevada cristalinidade, estabilidade térmica e luminescência. Adicionalmente, sínteses mais curtas e proporção metal:ligante 1:1 produziram redes com maior pureza de fase. Neste caso, o método assistido por micro-ondas se destacou devido ao rápido tempo de síntese. No segundo capítulo é apresentada a eficiência dessa MOF como marcador luminescente de munições. Com esta rede, além da detecção visual dos resíduos luminescentes (LGSR), técnicas como espectroscopia de emissão e microscopia eletrônica de varredura acoplada a espectroscopia por dispersão de energia (MEV/EDS) foram usadas para caracterizar e confirmar a presença do LGSR nos resíduos coletados, tanto da arma como das mãos do atirador. No terceiro capítulo são apresentados os dados relativos à avaliação da toxicidade oral aguda e subaguda da MOF [Eu(BTC)] em ratos. Para avaliação da toxicidade aguda, o protocolo 423 da OECD (Organisation for Economic Co-operation and Development) foi utilizado. Como resultado, nenhum sinal de toxicidade foi observado até mesmo para a dosagem mais elevada, e a dose letal média (DL50) foi estimada em 5000 mg/kg. Com isto, a MOF [Eu(BTC)] foi classificada na categoria menos tóxica do GHS (Globally Harmonized System). A toxicidade subaguda foi avaliada através da administração por 7 dias consecutivos de 300 mg/kg e, apesar de observados sinais graves de toxicidade, estes foram atribuídos à aspiração do material particulado para o pulmão, e não a toxicidade do marcador. Estes resultados atribuem a MOF [Eu(BTC)] uma elevada margem de segurança para aplicação como marcador de GSR. No quarto capítulo é proposto um método de codificação de munição baseado no uso de marcadores co-dopados [Y1-xLnx(BTC)] com os íons Eu3+, Sm3+, Tb3+ e/ou Yb3+. Após a realização de disparos, o marcador utilizado em cada munição foi identificado por MEV/EDS em função da composição química dos resíduos em 100% dos casos (sem que o analista tivesse conhecimento do marcador presente em cada munição). Além disso, foi possível estabelecer correlações atirador-arma-local do disparo através da composição dos resíduos em 89% dos casos. E no último capítulo é abordada a caracterização simultânea dos resíduos orgânicos e luminescentes por meio da microscopia Raman. Com a metodologia proposta, através de uma única medida foi possível determinar o tipo de marcador e pólvora utilizados, fornecendo um código muito seguro para caracterização e classificação inequívoca dos resíduos como provenientes de disparo de arma de fogo. Além disso, o LGSR atuou como sonda luminescente ajudando a coletar o OGSR em distâncias acima daquelas normalmente abordadas na literatura.
Gunshot residue (GSR) are physical evidences of great forensic value in firearms-related crimes. Despite its importance, there is a methodologic need for the characterization of GSR from non-toxic ammunition (NTA). In addition, the micrometric size of the generated particles makes its detection in a crime scene or on a suspect a hard task, which may produce false-negatives. In this sense, the use of luminescent materials has been proposed for chemical and optical marking of ammunition. This work presents the development of luminescent markers based on the metal-organic framework (MOF) [Ln(BTC)], since its synthesis, application and toxicity evaluation, as well as its ability to encode ammunitions and its simultaneous characterization with the organic gunshot residue (OGSR). Hence, this work is divided in five chapters. In the first chapter, aspects related to the synthesis of the MOF [Eu(BTC)] and its influence on the structural, thermal and spectroscopic properties are discussed. To this end, conventional hydrothermal synthesis and microwave(MW)-assisted hydrothermal synthesis, with different reaction times and metal:ligand proportions are analyzed. With the chosen methods, the MOF [Eu(BTC)] was obtained with high crystallinity, thermal stability and luminescence. However, faster synthesis and 1:1 metal:ligand proportion produced frameworks with higher phase purity. In this case, the MW-assisted method stood out due to the faster reaction time. In the second chapter, the efficiency of the MOF [Eu(BTC)] as a luminescent marker for ammunition is presented. With this framework, besides visual detection of the luminescent residues (LGSR), techniques as emission spectroscopy and scanning electron microscopy with energy dispersive X-ray spectroscopy (MEV/EDS) were used to characterize and confirm the presence of LGSR in the residues collected, both on the gun and in the shooter’s hand. In the third chapter, data related to the evaluation of acute and subacute oral toxicity of the MOF [Eu(BTC)] in rats is presented. For evaluation of acute oral toxicity, the OECD (Organisation for Economic Co-operation and Development) 423 guideline was used. As a result, no signs of toxicity was observed even at the highest dose, and the median lethal dose (LD50) estimated was 5000 mg/Kg. There by, the MOF [Eu(BTC)] was classified in the less toxic category of GHS (Globally Harmonized System). The subacute toxicity was evaluated by consecutive administration of 300 mg/Kg for 7 days and, despite severe toxicity signs were observed, they were attributed to the aspiration of the particulate material into the lungs, but not to the marker’s toxicity. These results give a high safety margin for application of this MOF as a GSR marker. In the fourth chapter an ammunition encoding method is proposed based on the use of the co-doped markers [Y1-xLnx(BTC)] with the ions Eu3+, Sm3+, Tb3+ and/or Yb3+. After shots, the markers used in each ammunition was identified by SEM/EDS due the chemical composition of the residues, in 100% of the cases (without the analyst’s knowledge of which marker was present in each ammunition). Furthermore, shooter-weapon-location correlations was established by the composition of the residues in 89% of the cases. And in the last chapter the simultaneously characterization of the organic and luminescent residues was performed by Raman microscopy. With the proposed methodology, the type of marker and gunpowder used were identified by a single run, providing a security code for its characterization and the unequivocal classification of the residues as coming from firearm discharge. Furthermore, the LGSR acted as a luminescent probe, helping to collect the OGSR further than those reported in the literature.

Ce travail de thèse rentre dans le cadre d’un projet de recherche appliquée mené à l’Institut National de Criminalistique et de Criminologie s’intitulant « développement d’un système intégral de détection et d’identification de résidus de tir » visant à doter le laboratoire de balistique chimique d’un outil performant pour la recherche et la caractérisation des résidus de tir aussi bien inorganiques qu’organiques. Comme nous l’expliquons dans le chapitre 1, l’analyse des résidus de tir est aujourd’hui essentiellement basée sur la mise en évidence par microscopie électronique à balayage des particules métalliques provenant de l’amorce. Cette pratique a des limites. Introductif, ce chapitre met en lumière la relation entre criminologie et criminalistique, donne un aperçu de la classification des armes et décrit les relations entre les armes de poing, les munitions, les résidus de tir et la criminalistique. La motivation de l’analyse de résidus organiques et plus particulièrement des stabilisants pour poudres propulsives y est aussi expliquée. Le but principal de ce travail étant le développement d’une méthode d’analyse des stabilisants par spectrométrie de masse en tandem couplée à la chromatographie liquide à haute performance (LC-MS/MS), ce premier chapitre aborde de façon détaillée le principe de fonctionnement d’un spectromètre de masse quadripolaire, qu’il soit avec simple quadripôle ou en tandem, et traite avec une attention particulière les aspects relatifs à la production d’ions, l’acquisition des données et la détection des ions.

Le chapitre 2 est consacré aux résultats et discussions. Comme point de départ de tous les travaux ultérieurs, l’optimisation du fonctionnement du spectromètre et plus particulièrement la détermination des « ions précurseurs » et des « ions produits » y est traitée en détails. De plus, l’étude de la fragmentation des ions précurseurs y occupe une place prépondérante et conditionne l’établissement d’une méthode de détection et d’acquisition des données. Dans ce même chapitre sont successivement traités la mise au point de la méthode chromatographique pour l’analyse des stabilisants par LC-MS/MS, le couplage LC-MS/MS, la collecte et préparation des échantillons, dont l’extraction sur phase solide (SPE). Disposant des procédures de traitement des échantillons et d’une méthode LC-MS/MS, il nous a été possible de mener l’étude de faisabilité de l’analyse des stabilisants dans les échantillons prélevés sur les mains d’un tireur. Cette étude fait l’objet d’une proposition de publication jointe en annexe. Pour être exploitable en criminalistique, ce travail est complété par une étude sur les fréquences d’observation des stabilisants pour poudres propulsives sur les mains des non-tireurs.

L’ensemble des résultats nous permet de dresser un bilan et proposer des perspectives décrites dans le chapitre 3. A cet égard, nous proposons de poursuivre les essais relatifs aux tests de persistance des résidus de stabilisant sur les mains des tireurs et d’entamer une étude sur la caractérisation des résidus de tir de la nitrocellulose. Du point de vue de l’exploitation des acquis de ce travail, nous suggérons que les méthodes et procédures développées soient mises à l’épreuve dans les affaires nécessitant l’analyse des prélèvements effectués sur les vêtements d’un suspect ou d’une victime. Cette mise à l’épreuve permettra de comparer l’efficacité de la méthode LC-MS/MS à celle de la technique SEM/EDX habituellement utilisée.

Le chapitre 4 est consacré aux matériels et méthodes détaillant notamment les procédures de collectes et de traitement des échantillons, les paramètres de fonctionnement du spectromètre de masse et les méthodes analytiques.

This thesis deals with a research project entitled "Development of an integral system of detection and identification of gunshot residues”, carried out at the Belgian National Institute of Criminalistics and Criminology (NICC). This project aims at providing the Laboratory of Chemical Ballistics, a powerful tool to detect and identify organic gunshot residues. For instance, the analyses of gunshot residues is presently performed mainly for characterizing metallic particles originating from the primer, using scanning electron microscopy coupled to energy dispersive X-ray microanalysis (SEM-EDX). However this technique has its limits and the goal of the thesis was the development of a method for the analysis of the stabilizers (and their derivatives) present in propellant powders with the use of tandem mass spectrometry coupled to high performance liquid chromatography (LC-MS/MS).

The introduction highlights the relations between Criminology and Criminalistics; it gives an outline of the classification of weapons, and describes how handguns, ammunitions, gunshot residues and Criminalistics can be linked when investigating criminal cases. The motivation of the analysis of organic gunshot residues and in particular the propellant powder stabilizers is also explained.

Chapter 1 deals in detail with the working principle of a quadrupole mass spectrometer, whether it is with a single quadrupole or composed of a tandem mass spectrometer. Important aspects connected with the ion production, the data acquisition and the ion detection are also considered.

Chapter 2 presents the results and discussions. It begins with the optimization of the operating conditions of the spectrometer, and focuses more specifically on the determination of “precursor ions" and "daughter ions”. The study of the precursor ion is more important because it is required for the choice of parameters involved in the data acquisition mode. The development of a liquid chromatography (LC) method and the procedures for collecting and preparing the samples are explained. Moreover, Chapter 2 summarizes the results of a feasibility study of the analyses of stabilizers in samples collected from the hands of a shooter. This study was published in a peer reviewed journal [1]. A complementary study on the frequencies of observation of stabilizers on the hands of non-shooter persons is reported at the end the Chapter.

The results allow also proposing perspectives which are described in Chapter 3. In this respect, the characterization of nitrocellulose residues and the study of the persistence of stabilizer residues on the hands of shooters should be undertaken. From the practical point of view, the developed methods and procedures should be tested in real cases which involve the analyses of the samples taken from the clothing of suspects and/or victims. These tests should allow an assessment of the LC-MS/MS method compared to the efficiency of the SEM/EDX technique currently used.

Chapter 4 is dedicated to the materials and methods; the sample collection and treatment procedures, as well as the working parameters of the mass spectrometer and the analytical methods are explained in detail.

[1]. Désiré Laza, Ph.D. Bart Nys, Ph.D. Jan De Kinder, Ph.D. Andrée Kirsch - De Mesmaeker, Ph.D. and Cécile Moucheron, Ph.D. Development of a Quantitative LC-MS/MS Method for the Analysis of Common Propellant Powder Stabilizers in Gunshot Residue. J. Forensic Sci, July 2007, Vol. 52, N° 4, 842-850.

Doctorat en Sciences
info:eu-repo/semantics/nonPublished

碩士
中央警察大學
鑑識科學研究所
104
The mainstream of the traditional indentification method of gunshot residue is using SEM / EDS to examine the inorganic gunshot residue particles, however, recently, confined to the widespread use of lead-free and non-toxic ammunition, making the indentification of inorganic gunshot residues being challenged nowadays. For lead-free and non-toxic ammunition having been stipulated to the ASTM criterion, however in the case of an established fairly complete indentification of SEM / EDS of inorganic gunshot residues, beening a part of the systematic indentifation, this thesis is to analysis the smokeless propellent and gunshot residues particles by the appearance characteristic and Raman microspectroscopy. Firstly, in this thesis, not only the composition of propellents and gunshot residues and characteristics by literature review, but how the Raman spectroscopy is applied to identify the gunshot residue in recent years, including the acheviment, the limits and how to overcome limitations and other parts are discussed, as to beening the reference to a follow-up experiment. In this thesis, propellent samples collected from 27 kinds of bullets, propellent samples on the shape, size and color are classified, and the results are displayed that in different powder samples were characterized by the appearance of a considerable difference. Followed by 780nm laser as an excitation source, the Raman spectrums of the propellent sample are measured, the results shows that some samples can be obtained directly Raman signal, and the remaining powder samples are subject to interference of the fluorescence and can not measure Raman signals, so one focus of this thesis is to evaluate the pre-treatment process to eliminate the fluorescence. In the pre-treatment process to eliminate the fluorescence assessed by reference the results of the selection using the mixed methanol / ethanol solvent and 2-butanone solvent as the pretreatment of propellent, the results show using the mixed methanol / ethanol solvent after one-time-washing the fluorescence interference can not be eliminated, and 2-butanone solvent after washing can reduce the fluorescence interference. Therefore, subsequent experiments using 2-butanone solvent washing method as the pretreatment of propellent samples and gunshot residues samples. In this thesis, the choice of 27 kinds of propellent standard bullets washed by 2-butanone solvent measuring by laser excitation wavelength of 780nm microscope Raman spectral, and according to the peak position and comparing with nitrocellulose smokeless powder additives standards, 27 kinds of propellent standards were analysised. The results showed that the Raman spectra of the propellent sample contain nitrocellulose main component peak, and can be successfully distinguished the additives such as nitroglycerin, 2-nitro-diphenylamine, methyl or ethylcentrilate, and dinitrotoluenes and other smokeless powder additives. Follow-up the propellent sample by Raman spectra peak position between the additive and spectral peaks at different locations are classified, the results show that 27 kinds of propellent samples can be divided into 20 subcategories, the discriminating power is 0.980. 6 kinds of propellent samples were put into shooting and collected the gunshot residues indentified by the laser excitation wavelength of 780nm microscopic Raman spectral. The results showed that some samples may detect direct Raman signal the rest still interfered by the fluorescence, after washed by 2-butanone solvent samples can detect remnants main component nitrocellulose, and may correspond to the source propellent. Another shooting test is to use different fabric surface, analysis showed that different materials will not affect the Raman spectrums of the gunshot residues.

碩士
中央警察大學
鑑識科學研究所
106
Gunshot residue (GSR) is an important type of trace evidence in gunshot incidents. It can be used to confirm suspicious bullet holes and to estimate the shooting distance. Furthermore, the analysis of gunshot residue samples collected from hands provides information of whether the person was present at the scene of gunshot events or had ever contact with someone or something related to gunshot incidents. The elemental analysis of gunshot residue can be used to categorize the primer type of ammunitions used and to narrow down the scope of investigation. The information mentioned above can also be used as the basis for the reconstruction of shooting incidents. Gunshot residue can be categorized into inorganic gunshot residue and organic gunshot residue. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) is the mainstream method for inorganic gunshot residue analysis, because it is capable of carrying out both morphological observation and elemental analysis simultaneously. According to the ASTM standard E1588-17「Standard Practice for Gunshot Residue Analysis by Scanning Electron Microscopy/Energy Dispersive X-Ray Spectrometry」, particles classified as characteristic to GSR shall have elemental composition of Pb-Sb-Ba or Pb-Ba-Ca-Si-Sn. With the rising environmental concerns and health awareness, some ammunition manufacturers have removed heavy-metal ingredients from the primer mixtures and totally enclosed the lead bullet core. Gunshot residues generated from the firing of heavy-metal-free ammunitions are not characteristic to GSR. Besides, gun control laws are extremely strict in Taiwan, hence homemade firearms and ammunitions are frequently used by criminals. Gunshot residue generated from the discharge of homemade ammunitions usually contained elemental composition non-characteristic to GSR. Thus the analysis of GSR became a challenge for the forensic scientists when the heavy-metal-free or homemade ammunitions were involved in the investigated gunshot incidents. In order to correctly understand the elemental composition and morphological features of GSR generated from domestic homemade ammunitions, gunshot residue samples were collected from real gunshot cases involving homemade handgun ammunitions. Since there were two different primer structures found in domestic homemade ammunitions, primer bar type and primer cup type, unfired ammunitions and spent cartridge cases were collected from eight randomly chosen gunshot cases for each primer-type homemade cartridges. Test firings were conducted using three rounds of homemade ammunitions from each case. Aluminum plates were used as targets for test firings. Gunshot residue samples were collected from the rim of the entrance hole and the inner surface of the petals protruded backward around the bullet hole on the aluminum plate and the flash hole inside of the spent cartridge case for each test firing. All GSR samples were subject to SEM/EDS analysis. Another round of homemade ammunition from each case was disassembled and the major parts of the ammunition were analyzed using SEM/EDS to determine their elemental compositions. Primer mixtures collected from four types of toy gun primer products were also subject to SEM/EDS analysis to understand the possible sources of primers used in domestic homemade ammunitions. The results indicate that the elemental composition of the major parts of homemade ammunitions would contribute to the elemental profiles of gunshot residues. Spherical GSR particles were detected in all samples collected from the aluminum plate targets and spent cartridge cases in all test firings and case samples. The major elemental profile of GSR generated from homemade ammunitions was found to be P-Cl-K-Ca which is not characteristic to GSR. Elementals such as Al, Si, S, Fe, Cu, Zn, Pb, Ba, Mg, or Ti were also detected in GSR samples. Characteristic GSR particles were detected in samples from two cases where only one Pb-Sb-Ba particle was detected in one case and one Pb-Ba-Ca-Si-Sn particle was detected in the other case. With only one exception that GSR particles contained elemental profiles consistent with with GSR, such as Pb-Ba, Pb-Ca-Si, Pb-Al, Sr, and Ti-Zn, were detected in all GSR samples collected from the studied gunshot cases. The results show that the elemental profiles of the homemade ammunition gunshot residues were significantly different from the characteristic ones. These results might lead to false negative conclusions of GSR or false positive conclusions of GSR generated from non-corrosive primer mixtures of rim-fired ammunition. We found that GSR elemental profiles generated by ammunitions from some different gunshot cases were similar to each other. And GSR elemental profiles from cartridges with the same head stamps from the same shooting case were sometimes found to be different. In order to avoid incorrect conclusions of GSR analysis to be reached and to enhance the reliability and evidential value of analysis results, it is recommended that the elemental profiles of unknown GSR samples should be compared with those detected in the known GSR samples collected from spent cartridge cases or the inner surface of the barrel of shooting gun of the same shooting case. According to the GSR analysis results where elemental profile of Pb-Ba was frequently detected, it is postulated that most gunpowder used in local homemade ammunitions was acquired from the stud gun blank ammunitions. And small part of the gunpowder might be obtained from fireworks due to the Cl-K-Ca elemental profile was detected. The primers used might either come from the commercial toy gun primer products or the blank cartridges of stud guns. Although most of the elemental profiles of GSR generated from studied homemade ammunitions were not characteristic to GSR, the morphological features of these GSR particles, the identification of cartridge head stamps, and the analysis of some unusual component parts from the homemade cartridges can still provide useful information for tracing down the origins of the homemade cartridges.

碩士
中央警察大學
鑑識科學研究所
87
Gunshot residues(GSR) samples are usually analyzed by inorganic and/or organic analytical methods. Scanning electron microscopy /energy dispersive X-ray analysis(SEM/EDX) is widely used to observe the morphological characteristics of inorganic GSR particles and to determine their unique elemental composition simultaneously. A variety of chromatographic techniques using various detectors are employed to analyze organic GSR. Usually, the results can provide complementary and additional information when inorganic residues have not been detected. Three subjects were studied in this work. Firstly, airborne GSR samples were collected during and after test firings, samples were then analyzed using SEM/EDX. The results indicated that GSR particles suspended in the air for as long as four hours after shooting. The amount and the maximum size of detected inorganic GSR particle in each sample was gradually decreased as the time passed after test firing. Anyone who entered the scene during or soon after the occurrence of a shooting might inhale and retain airborne GSR on his nasal mucus. thus the detection of GSR in nasal mucus can only be used to prove a person has been on the scene rather than to prove he has fired a gun. This work was secondly concentrated on the detection of GSR while disposable gloves were worn by firer during shooting. The results revealed that GSR were easily detected on the surface of used gloves without any interference from powdery lubricants. Driving a car after shooting led to the transfer of GSR to the steering wheel. GSR could then be detected on used gloves and the steering. In addition to the used gloves, GSR were also detected in samples collected from shooter's hair,nostrils,eyebrows and forehead. Finally, a high-performance thin-layer chromatographic procedure was developed for the analysis of propellant flakes. This procedure was proved to be efficient in the detection of stabilizer ingredients in both unfired propellant and shooting residues of propellants.

碩士
中央警察大學
鑑識科學研究所
106
In the cases of gun-related activities in Taiwan, homemade ammunitions and guns are frequently used. Because the compositions of the primer and the propellant of domestic homemade ammunitions are different from those of foreign commercial ammunitions, there could be a false negative result if we only choose the traditional inorganic characteristic elements, Pb, Sb and Ba, as the targets to identify the gunshot residues (GSR) of homemade ammunitions. This condition is similar to which of non-toxic ammunitions. The GSR of homemade ammunitions also could be misidentified as that they are originated from the commercial ammunitions with non-corrosive primer. To avoid the misidentifications mentioned above, the corresponding inorganic characteristic elements should be discussed on a case-by-case basis and the analysis of organic components should be considered to improve the accuracy of the identification results. 　　Talking about the identification of organic GSR, micro-FTIR and micro-Raman spectroscopies have the advantages of non-destructive analysis and rapid identification. Both spectroscopies have been applied in the field of forensic science for several kinds of evidence. Recent years there were several researches about the analysis of smokeless gunpowder and GSR using micro-FTIR and micro-Raman. But few related researches about the analysis of gunpowder of homemade ammunitions were published. 　　In this study, the samples of domestic homemade ammunitions were collected from the real criminal cases. According to the differences in primer structure, the samples were divided into two types: the primer bar type and the primer cup type. Ammunitions were collected from five different cases for each type of primer structures, so there were samples from 10 cases in total. For each case there was an unfired ammunition disassembled and the gunpowder of which was analyzed using micro-FTIR and micro-Raman to realize its organic composition. The results showed that most homemade ammunitions of both primer types in this study contained crystalline particles, transparent spherical smokeless gunpowder, and viscose particles, which were suspected of originating from commercially available blank ammunitions for nail gun and commercially available viscose products. So five kinds of both commercially available products mentioned above were analyzed and compared with particles contained in the homemade ammunitions. 　　It was found that all gunpowder contained in the five kinds of blank ammunitions for nail gun were double-base smokeless gunpowder, and were consistent with most of the gunpowder found in homemade ammunitions in appearance. Further comparisons of the additive components of the smokeless gunpowder indicated that gunpowder contained in the homemade ammunition in one of ten cases in this study didn’t originate from the five kinds of blank ammunitions for nail gun. With viscose products, five kinds of commercially available products were analyzed and four kinds of them were alkyd resins and one kind of them was phenolic resin. According to the organic spectral peaks of the functional groups, the homemade ammunitions sampled in this study didn’t contain particles of phenolic resins. That is, the viscose particles contained in those homemade ammunitions couldn’t be from the commercially available phenolic resin products. 　　In each case, three ammunitions were fired and GSR of them were sampled from the surface of the shooting target, the inner side of the gun barrel and the inside of the cartridge case to analyze organic components of the GSR. Micro-FTIR were suitable for all GSR samples in this study, while micro-Raman was susceptible to fluorescence of them. However, the Raman spectra of some samples can still be evaluated together with the infrared spectra to confirm the location of characteristic peaks. It was found that the GSR samples contained most kinds of particles contained in the unfired ammunitions. However, the crystalline particles of primary high-explosive were significantly reduced, while the number of the kinds of viscose particles were found to be more than those contained in the unfired ammunitions. Most kinds of the viscose particles found in the GSR samples were acrylate resins. And in one of these cases, the sample of viscose particles of the GSR was found to be ethyl cyanoacrylate, which is consistent with one of the commercially available viscose products sampled in this study. With the smokeless gunpowder, GSR in four of ten cases were found to contain particles of smokeless gunpowder not found in the unfired ammunitions from the same cases. 　　Based on the research results mentioned above, it was found that: (1) Compositions of the gunpowder in homemade ammunitions were not related to their primer structures or headstamps. And they may not be consistent with each other even though those homemade ammunitions were identical in appearance. (2) Numbers of kinds of particles contained in part of the homemade ammunitions were more than those contained in commercial ammunitions. There were crystalline particles, transparent spherical smokeless gunpowder and viscose particles found in the homemade ammunitions and the source of them may be commercially available blank ammunitions for nail gun and viscose products. This result made the homemade ammunitions distinguishable from commercial ammunitions. And the information of choices of the commercial blank ammunitions and viscose products could be possibily used for a further classification. (3) In addition to the results of inorganic elemental analysis of the GSR, it was possible to get more information and enhance the accuracy of the identification results if the stereo microscope and organic spectroscopies were also used. (4) Micro-FTIR is better than micro-Raman for the analysis of GSR of domestic homemade ammunitions without the sample pretreatment. 　　According to the research results in this study, a recommended procedure was proposed in order to determine whether the GSR are originated from commercial ammunitions or not. Firstly, use stereo microscope to pick particles in the unknown GSR sample and then analyze their organic components by FTIR and Raman microspectroscopy to confirm whether the double-base smokeless powder is contained and whether it is transparent spherical or not. If all of the above are positive, then the GSR are more likely not originated from commercial ammunitions. If there is smokeless gunpowder in the unknown GSR sample, which is not transparent spherical, take the existence of crystalline or viscose particles into consideration and make a comprehensive assessment. If smokeless gunpowder is not found in the unknown GSR sample, or only smokeless gunpowder which is not transparent spherical is found in the unknown GSR with no crystalline and viscous particles, the identification should be dependent on the result of inorganic elemental analysis. Following the proposed procedure, 76% of the GSR samples collected from the surface of the shooting targets and the inner side of the gun barrel were confirmed as GSR in the study, and also were identified more likely not to be originated from commercial ammunitions. 　　Compared with the GSR identification only by traditional inorganic elemental analysis in which characteristic element Pb, Sb and Ba were chosen as the target, the research results in this study can not only effectively reduce the possibility of false-negative identification, but also provide us a procedure to identify whether the GSR is originated from commercial ammunitions when the GSR sample was collected from the surface of the shooting target without any other further information of the crime scene. And the result of the identification may be useful in the preliminary criminal investigation.

碩士
中央警察大學
鑑識科學研究所
99
Forensic firearms examiners are usually able to identify the gun discharged in a shooting incident via the examination of the individual striations on the rifling marks of the fired bullets. However, the recovered projectiles can be so damaged that the quality of marks is not sufficient for comparison. Color tests employed to confirm bullet holes may also yield inconclusive results when cartridges using non-toxic primers are fired. Thus the analysis of elemental composition of bullet jacket fragments, bullet wipes around the bullet holes, and the gunshot residues deposited inside the fired barrels might provide other kinds of information for the investigation of gunshot incidents. Eleven kinds of 9 mm Luger cartridges were test fired using both Glock 17 and Beretta 92 FS pistols in this study. The bullet jacket fragment, bullet wipe around the bullet hole, and the gunshot residues left inside the fired barrel of each test firing were collected and subsequently digested using nitric acid. The sample solutions were then analyzed using inductively coupled plasma mass spectrometry (ICP-MS). Five out of the eleven kinds of studied cartridges are duty cartridges of the domestic police forces purchased by the National Police Agency (NPA) in five different years. Their head stamps all contain the abbreviation of NPA. The other six kinds of cartridges without the head stamps of NPA are designated as non-NPA cartridges in this study. The results show that the concentration ratio of copper to zinc (Cu/Zn) detected in bullet jackets could be used to differentiate non-NPA bullets from the NPA cartridges. The concentration ratio of copper to silver (Cu/1000Ag) detected in bullet jackets provided useful information for the classification of bullets originated from different sources. The concentration ratios of lead to copper (100Pb/Cu) and barium to copper (100Ba/Cu) detected in gunshot residues collected from the inside of the fired barrels were successfully used to identify the primer type of the fired cartridges as being either the non-corrosive primer or the non-toxic primer. Because the elemental profiling of the bullet wipe sample was affected by the gunshot residues deposited inside of the barrel from previous shootings, it was possible to detect heavy metals from primer residues, such as lead and barium, in bullet wipe samples even when cartridges with non-toxic primers were test fired. As a result, these heavy metal elements were also useful for the identification of bullet holes even when the cartridges with non-corrosive primers were discharged. Zinc peroxide and aluminum powder are common components of primer mixtures. Thus the concentration ratios of zinc to copper (Zn/Cu) and aluminum to copper (Al/Cu) detected in samples collected from the gun barrels and bullet wipes were usually higher than that detected in bullet jacket samples. This result also provided another way via using the concentration ratios of Zn/Cu and Al/Cu in bullet wipe sample to confirm a suspected bullet hole if lead and barium were not detected. The metal jackets of the S&B cartridges test fired in this study were reported to be composed of three layers of metals. The unusual structure and silver color of the jacket were useful to discriminate S&B bullets from the other kinds of bullets. The elemental profiling detected in the S&B jackets was significantly different from that of the other kinds of bullet jackets. The elements of Fe, Mn, Al, Cu, Zn and Ni were detected as major ingredients in S&B bullet jackets, however, only Cu and Zn were detected as major ingredients in the other kinds of bullet jackets. Because tin foil was used to cover the primer mixtures of the Berdan type primer used in the S&B cartridges, the concentration ratios of tin to copper (Sn/Cu) in gunshot residues collected from the inside of the gun barrel and bullet wipe were greater than that of the bullet jacket sample. This study developed practical procedures via quantitative analysis of metal elements to discriminate the bullet jackets originated from different sources and to identify the primer type of fired cartridge, and to confirm the suspected bullet holes. However, more samples should be analyzed in the future to improve the reliability and validity of the developed procedures to facilitate the application of the procedures to real case samples.

Tese de mestrado em Química, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2013
Nos nossos dias a criminalidade representa uma das maiores chagas sociais. Na grande maioria dos crimes contra a vida, as armas de fogo estão presentes e, por essa razão, os elementos municias, os resíduos de disparo e até as próprias armas de fogo são dos objetos mais encontrados no local do crime. Em todos os casos uma grande questão se levanta “Quem disparou a arma?”. Estudos anteriores sobre gunshot residues (GSR) e pólvora não deflagrada, focam apenas os constituintes inorgânicos, que são analisados através de microscopia eletrónica de varrimento ou técnicas similares. Uma vez que estes constituintes são praticamente invariáveis, independentemente da munição, do seu fabricante ou país de origem, esta análise permite apenas identificar o material como sendo ou não GSR. Assim sendo, é fundamental a realização de outros tipos de estudos do GSR bem como da pólvora não deflagrada. Uma das formas de contribuir com nova informação para a investigação é estudar os compostos orgânicos da pólvora através de Cromatografia Gasosa acoplada à Espectrometria de Massa (GC-MS), com particular atenção à Difenilamina (DPA) e à Etil-centralite (EC). Estes dois compostos são estabilizadores da pólvora, altamente reativos, ou seja, durante a sua ação de estabilização vão se degradando levando à formação de derivados. Neste estudo identificaram-se os estabilizadores presentes na pólvora não deflagrada e nos GSR de munições disparadas pertencentes ao mesmo lote das não deflagradas, mantidas sobre condições de armazenamento conhecidas e controladas. Através da comparação qualitativa e quantitativa dos estabilizadores e respetivos derivados da pólvora não deflagrada e do GSR, conclui-se que é possível chegar a uma concordância relativa entre ambos. Isto porque, após a análise qualitativa, foi realizada a análise quantitativa onde se verificou um padrão, relativamente aos valores obtidos, isto é, obteve-se na maioria dos casos um decréscimo da quantidade de estabilizador e derivados, que variou entre os 96,83 % e os 99,98 %, com exceção em um dos casos cujo decréscimo observado foi de 70%. Este aspecto leva a conclusões muito interessantes, sendo possível a realização destas análises para exclusão de um suspeito ou, por outro lado, fortalecer ainda mais as suspeitas sobre determinado individuo. Futuramente, através de um estudo estatístico, poderá ser possível realizar identificações com grande grau de certeza utilizando este tipo de compostos para análise. Assim verificou-se que o que inicialmente se apresentava como uma desvantagem na identificação das pólvoras, isto é, a grande reatividade dos seus constituintes orgânicos, nomeadamente dos seus estabilizadores, acabou por se tornar um aliado das ciências forenses, permitindo uma grande concordância entre as pólvoras não deflagradas e o GSR.
Nowadays the crime represents one of the largest social wounds. In the vast majority of crimes against life, firearms are present, and therefore, ammunition elements, gunshot residues, firearms are the most found objects at the crime scene. In all cases a major question arises "Who fired the gun?". Previous studies of gunshot residues (GSR) and gunpowder not triggered, focus only on inorganic constituents, which are analyzed by scanning electron microscopy or similar techniques. Since these constituents are practically unchanged, regardless of ammo, the manufacturer or country of origin, this analysis allows only identify the material as being or not GSR. Therefore, it is critical to conduct other studies of GSR and gunpowder not triggered. One way to contribute new information for research is to study the organic compounds of gunpowder by gas chromatography coupled to mass spectrometry (GC-MS), with particular attention to Diphenylamine (DPA) and Ethyl-of centrality (EC). These two compounds are stabilizers of the powder, highly reactive, ie during its stabilizing action will degrade leading to the formation of derivatives. This study identified the stabilizers present in the powder not triggered and the GSR ammunition fired from the same batch of unexploded ordnance, kept under storage conditions known and controlled. Through the qualitative and quantitative comparison of stabilizers and their respective derivatives of gunpowder not triggered and the GSR, it is concluded that it is possible to reach a relative agreement between them. This is because after the qualitative analysis, quantitative analysis was performed where a pattern is found, i.e. obtained in most cases a decrease of the amount of stabilizer and derivatives, which ranged from 96.83% to 99.98 %, except in one case which observed decrease was 70%. This aspect leads to very interesting conclusions, it is possible at this time, these analyzes to exclude a suspect, or otherwise further strengthen suspicions about a particular individual. Eventually through a statistical study may be possible to perform identification with a high degree of certainty by the use of such compounds for analysis. Thus it was found that what initially appeared as a disadvantage in the identification of powders, ie, the great reactivity of organic constituents, including their stabilizers, eventually became an ally of forensic science, enabling a broad agreement between the powders and unexploded GSR.

Gunshot residue (GSR) has been analyzed in forensic laboratories since 1933 when the dermal nitrate test originated. (1) Detection and analysis of GSR has since developed with the invention and implementation of instrumentation. Since the 1960s, inorganic gunshot residue (IGSR) has been the primary focus for GSR analysis. (2) As disadvantages like omitting lead from ammunition and the transient properties of IGSR are researched, it is clear that a new approach is needed. Organic gunshot residue (OGSR) analysis has the potential to become the novel approach for GSR analysis because OGSR does not have the same transient properties as IGSR. (3) The compounds are lipophilic and are therefore more likely to remain on the shooter’s hands or face. (4) OGSR can be analyzed through a myriad of instrumentations, including High Performance Liquid Chromatography/Mass Spectrometry(HPLC/MS). Analysis with HPLC/MS allows for customizable mobile phases, gradients, columns, and ionization to ensure the complete detection of OGSR. Using a Shimadzu Ultra Performance Liquid Chromatography (UPLC) coupled with an AB Sciex Q-Trap 4000 MS/MS, a method is optimized for the detection of Diphenylamine (DPA), Nitroglycerin (NG), and Ethyl Centralite (EC). The next steps for experimentation are summarized and include an elution study and a time-course study.

Gunshot primer residue (P-GSR) is released from the openings of a firearm when it is discharged12,13. P-GSR is made of microscopic particles that are considered characteristic of being derived from firearm ammunition when composed of barium (Ba), lead (Pb), and antimony (Sb) and have the correct morphology4. Morphology describes the shape of the P-GSR particle, which can be spherical, irregularly shaped, and must be non-crystalline. Forensic labs are commonly requested to test for the presence of P-GSR on evidential items, such as hands, clothing, vehicles, and gloves, in order to provide circumstantial evidence showing that they were, in some way, possibly involved with a shooting. Occasionally these evidential items are also expected to undergo fingerprint processing to potentially link someone to a crime. Latex gloves are often utilized in the commission of a crime with the impression that fingerprints cannot be left behind, however latent prints can often be developed on this non-porous material. Due to the evidential value of fingerprints and in order to ensure that potential prints are not damaged during P-GSR collection, latent print development is routinely performed first. Considering that P-GSR particles are easily dislodged, it is possible that some loss of P-GSR may occur during latent print processing. The purpose of this study was to evaluate the effect of processing a non-porous item for latent fingerprints on the subsequent recovery and detection of P-GSR. Latex gloves were worn during the discharge of either a pistol or a revolver and then processed for latent prints by undergoing cyanoacrylate fuming followed by either white powder or yellow dye. The latex gloves were then sampled for P-GSR using aluminum stubs containing an adhesive coating which were dabbed over the gloves until they loss their tackiness. The stubs were then carbon coated using a Denton Vacuum Desk IV in order to prevent charging in the analytical instrument. Utilizing a JEOL JSM-6460LV Scanning Electron Microscope (JEOL USA Inc., Peabody, MA coupled with an EDAX Apollo X Analyzer (EDAX Inc., Mahwah, NJ) and EDAX Genesis GSR Software, the stubs were processed for three-component particles characteristic of P-GSR. It was determined that P-GSR can still be recovered on latex gloves after undergoing latent print processing involving cyanoacrylate fuming followed by either white powder or yellow dye processing. Three-component particles were found on both the interior and exterior of the latex gloves after being processed for latent prints. On average, 33 P-GSR particles were found on the exterior of the gloves and four P-GSR particles were found on the interior of the gloves. Although significantly less were found on the interior of the gloves (<10), it is recommended that both sides of gloves be stubbed when collecting P-GSR for the greatest chances of collecting three-component particles if they are in fact present on a pair of gloves. Although more particles were found on the gloves that were not processed for latent prints, a sufficient number of particles (≥3 particles) were consistently found on the latex gloves after undergoing latent print processing to provide a positive P-GSR result according to the Massachusetts State Police Crime Lab guidelines for P-GSR analysis. Therefore, this research shows that latex gloves can first be processed for latent prints and then subsequently be processed for P-GSR effectively in order to try and obtain both forms of evidence for a case.