Characterization of the volatile organic compounds present in the headspace of decomposing animal remains, and compared with human remains
ABSTRACT Human Remains Detection (HRD) dogs can be a useful tool to locate buried human remains because they rely on olfactory rather than visual cues. Trained specifically to locate deceased humans, it is widely believed that HRD dogs can differentiate animal remains from human remains. This study analyzed the volatile organic compounds (VOCs) present in the headspace above partially decomposed animal tissue samples and directly compared them with results published from human tissues using established solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS) methods. Volatile organic compounds present in the headspace of four different animal tissue samples (bone, muscle, fat and skin) from each of cow, pig and chicken were identified and compared to published results from human samples. Although there were compounds common to both animal and human remains, the VOC signatures of each of the animal remains differed from those of humans. Of particular interest was the difference between pigs and humans, because in some countries HRD dogs are trained on pig remains rather than human remains. Pig VOC signatures were not found to be a subset of human; in addition to sharing only seven of thirty human-specific compounds, an additional nine unique VOCs were recorded from pig samples which were not present in human samples. The VOC signatures from chicken and human samples were most similar sharing the most compounds of the animals studied. Identifying VOCs that are unique to humans may be useful to develop human-specific training aids for HRD canines, and may eventually lead to an instrument that can detect clandestine human burial sites.
SourceAvailable from: Matthew L Dawson[Show abstract] [Hide abstract]
ABSTRACT: Aerosol particles are ubiquitous in the atmosphere and have been shown to impact the Earth’s climate, reduce visibility, and adversely affect human health. Modeling the evolution of aerosol systems requires an understanding of the species and mechanisms involved in particle growth, including the complex interactions between particle- and gas-phase species. Here we report studies of displacement of amines (methylamine, dimethylamine, or trimethylamine) in methanesulfonate salt particles by exposure to a different gas-phase amine, using a single particle mass spectrometer, SPLAT II. The variation of the displacement with the nature of the amine suggests that behavior is dependent on water in or on the particles. Small clusters of methanesulfonic acid with amines are used as a model in quantum chemical calculations to identify key structural elements that are expected to influence water uptake, and hence the efficiency of displacement by gas-phase molecules in the aminium salts. Such molecular-level understanding of the processes affecting the ability of gas-phase amines to displace particle-phase aminium species is important for modeling the growth of particles and their impacts in the atmosphere.The Journal of Physical Chemistry C 12/2014; 118(50):29431-29440. DOI:10.1021/jp506560w · 4.84 Impact Factor
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ABSTRACT: Increased characterisation of decomposition odour has improved existing knowledge regarding the decomposition volatile organic compound (VOC) profile of carrion. Validation of this dynamic decomposition VOC profile is required in order to characterise the variables that affect their production. This study was performed to determine whether the decomposition VOC profile produced under field conditions differed between summer and winter in an Australian environment. Outdoor studies were conducted using pig carcasses as human analogues in order to assess seasonal variation in the decomposition process. Common decomposition VOCs were identified using comprehensive two-dimensional gas chromatography – time of flight mass spectrometry (GC×GC-TOFMS). Fewer compounds and reduced abundance of VOCs was observed during winter. Relationships between the levels of detected decomposition VOCs and weather variables were established to be stronger in winter. Weak relationships during summer suggested the potential that an underlying variable (e.g. microbial activity, insect activity) had a stronger relationship to the abundance of decomposition VOCs. The seasonal robustness of the decomposition VOC profile is important to fields relying on the presence of a decomposition odour, i.e. search and recovery of victims in mass disasters, homicides, and missing persons cases.Analytical methods 11/2014; 7(2). DOI:10.1039/C4AY02321H · 1.94 Impact Factor
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ABSTRACT: Twelve pig carcasses were buried in single, shallow and deep (30 and 90 cm, respectively) graves at an experimental site near Ottawa, Ontario, Canada, with three shallow and three deep wrapped in black plastic garbage bags. An additional six carcasses were left at the surface to decompose, three of which were bagged. Six reference pits without remains were also dug. The objective of this three-year study was to examine the biogeochemistry and utility of nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) in grave detection and whether grave depth or cadaver condition (bagged versus bare) affected soil pore air concentrations and emission of the three gases. Graves showed significantly higher (α = 0.05) concentrations and surface fluxes of N2O and CO2 than reference pits, but there was no difference in CH4 between graves and reference pits. While CH4 decreased with depth in the soil profiles, N2O and CO2 showed a large increase compared to reference pits. Shallow graves showed significantly higher emissions and pore air concentrations of N2O and CO2 than deep graves, as did bare versus bagged carcasses.Forensic Science International 12/2014; 247. DOI:10.1016/j.forsciint.2014.12.002 · 2.12 Impact Factor