A new method for collection and identification of gunshot residues from the hands of shooters

This work presents a novel collection method for gunshot residues (GSR) using a sampling procedure based on ethylenediaminetetraacetic acid (EDTA) solution as a complexing agent on moistened swabs. Detection was via a sector-field inductively coupled plasma mass spectrometry (HRICP-MS). The proposed collection and analytical method allowed detection of antimony (Sb), barium (Ba) and lead (Pb) after .38 shot tests. at detection limits of less than 1 microg L(-1) in four different areas of the hands of volunteers. This paper includes a discussion concerning hand areas near the thumb and forefinger as being more suitable for GSR collection as well as a comparison between differences observed using 2% diluted EDTA. 2% nitric acid solution, and simple deionized water as collecting solutions, proving the superior efficiency of EDTA in GSR recoveries.     

Identification of gunshot residues in fabric targets using sector field inductively coupled plasma mass spectrometry technique and ternary graphs

During criminal investigations involving firearms, the detection of gunshot residues (GSRs) is one of the most important evidences. In the present study, a new method to identify trace evidences of GSRs, deposited around the bullet entrance hole, in different types of fabrics used as targets, is described. The experiments were carried out using a 0.38-inch caliber revolver, and 9-mm and 0.40-inch caliber pistols. Testimonies of 2.25 cm(2) of the fabrics were cut around the bullet entrance and digested with 10% nitric acid. Antimony, barium, and lead were analyzed in the remaining solution using a sector field inductively coupled plasma mass spectrometer. The concentrations of the elements were detected at levels up to few microgram per square centimeter. The use of ternary graphics allowed us to identify specific patterns of distribution for blank samples and the clear distinction between the revolver and pistols used.     

Carbon and nitrogen stable isotopes as indicative of geographical origin of marijuana samples seized in the city of São Paulo (Brazil)

The drug trafficking is one of the most serious problems related to the Public Safety in Brazil, especially in the most populous areas of the country, as is the case of the city of São Paulo. In this work, it was developed a methodology that can help tracking the traffic routes of marijuana samples seized in the city of São Paulo, based on stable carbon and nitrogen isotopes, which are related to the climate and plant growth conditions. A model to classify the origin of unknown samples was built using linear discriminant analysis based on about 150 samples apprehended in the main producing regions of the country. Results for 76 samples seized in the city of São Paulo showed that most of them were cultivated in a humid region with the same origin as those from Mato Grosso do Sul. The provenance of 13 outliers samples from Northeast region (an important producing region) also were evaluated and some of them presented same profile of those from Mato Grosso do Sul, pointing to the existence of the traffic routes between the Northeast and Midwest region, probably as a consequence of the intensive field raids by Brazilian Federal Government since 1999.     

Sourcing Brazilian marijuana by applying IRMS analysis to seized samples

The stable carbon and nitrogen isotopic ratios were measured in marijuana samples (Cannabis sativa L.) seized by the law enforcement officers in the three Brazilian production sites: Pernambuco and Bahia (the country's Northeast known as Marijuana Polygon), Pará (North or Amazon region) and Mato Grosso do Sul (Midwest). These regions are regarded as different with respect to climate and water availability, factors which impact upon the isotope fractionations of these elements within plants. It was possible to differentiate samples from the dry regions (Marijuana Polygon) from those from Mato Grosso do Sul and Pará, that present heavier rainfall. The results were in agreement with the climatic conditions of the suspected regions of origin and this demonstrates that seized samples can be used to identify the isotopic signatures of marijuana from the main producing regions in Brazil.     

National development policy and external dependence in Latin America

Many of Latin America's Roman Catholic leaders—clerical and lay—have moved away from previously dominant conservative political positions, as a result both of doctrinal changes decreed by Rome (Pope John and the Council) and of the widespread failure of meaningful development in their, societies. But in most places the position of the hierarchy is only marginally different from that of the government in power (save on issues of basic human rights where these are systematically denied) and the impact of the radical minority is small. Though the church wishes its voice to be heard, it is doubtful whether its views will make much difference: secularization has gone far among decision‐makers, and those who still listen to the clergy are mostly conservative middle‐class women and an uneducated peasantry, still caught up in traditional folk beliefs.     

Voltammetric analysis of luminescent markers in gunshot residues

Currently, SEM-EDS is used to detect gunshot residue (GSR) from the presence of Ba, Pb, and Sb in the sample. However, the development of new nontoxic ammunition (NTA) has prevented conventional metals from being found. In this work, we aim to determine the presence of an inorganic luminescent chemical marker based on rare earth in gunshot residues using the technique of squarewave voltammetry (SWV). After firing, the luminescent complex [(Eu₂Zr)(btc)₃(Hbtc)_0.5.6H₂O], which is used as a chemical marker, can be detected under a UV lamp. An aqueous solution with 0.1 mol L⁻¹ KCl as supporting electrolyte can be easily collected on carbon paste electrode surfaces for SWV analysis A = 100 mV, f = 10 Hz, and step potential of 5 mV are required. The luminescent marker incorporated into the carbon paste electrode showed two anodic peak currents in the region of 0.4 V (vs Ag/AgCl) and at 0.75 V (vs Ag/AgCl) and also a cathodic one in 0.4 V (vs Ag/AgCl). SEM-EDS was able to analyze the same voltammetric results for conventional and nontoxic ammunition containing the luminescent marker. Therefore, voltammetry and SEM-EDS are valid for detecting the new residue marker in GSR. Despite this, the electrochemical method is still more advantageous because of its low cost and lack of expensive equipment and supplies in forensic laboratories.