Characterization of the volatile organic compounds present in the headspace of decomposing animal remains, and compared with human remains

Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89512, USA.
Forensic science international (Impact Factor: 2.14). 03/2012; 220(1-3):118-25. DOI: 10.1016/j.forsciint.2012.02.007
Source: PubMed


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.

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    • "The animals were prepared in a local slaughterhouse in compliance with EU regulations. During euthanasia, efforts were made to reduce blood loss, as blood plasma is considered an additional fluid Table 1 An overview of the main factors affecting the decomposition rate [3] [9] [10] [12] [18] [24] [31] [32] [35]. "
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    ABSTRACT: Field experiments were devised to mimic the entrapment conditions under the rubble of collapsed buildings aiming to investigate the evolution of volatile organic compounds (VOCs) during the early dead body decomposition stage. Three pig carcasses were placed inside concrete tunnels of a search and rescue (SAR) operational field terrain for simulating the entrapment environment after a building collapse. The experimental campaign employed both laboratory and on-site analytical methods running in parallel. The current work focuses only on the results of the laboratory method using thermal desorption coupled to comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (TD-GC×GC-TOF MS). The flow-modulated TD-GC×GC-TOF MS provided enhanced separation of the VOC profile and served as a reference method for the evaluation of the on-site analytical methods in the current experimental campaign. Bespoke software was used to deconvolve the VOC profile to extract as much information as possible into peak lists. In total, 288 unique VOCs were identified (i.e., not found in blank samples). The majority were aliphatics (172), aromatics (25) and nitrogen compounds (19), followed by ketones (17), esters (13), alcohols (12), aldehydes (11), sulfur (9), miscellaneous (8) and acid compounds (2). The TD-GC×GC-TOF MS proved to be a sensitive and powerful system for resolving the chemical puzzle of above-ground "scent of death". Copyright © 2015 Elsevier B.V. All rights reserved.
    Analytica Chimica Acta 04/2015; 883. DOI:10.1016/j.aca.2015.04.024 · 4.51 Impact Factor
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    • "Methods to expedite locating clandestine graves have been developed where surface clues are lacking and where the content of a potential grave is unknown [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]. Changes in soil properties have been examined [5,7,10,13,15–17] and volatile chemical compounds and odors that could indicate the presence of buried remains [18] [19] [20] [21] [22] [23] [24] have been identified. "
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    ABSTRACT: A fast and simple screening procedure using solid-phase microextraction and gas chromatography-mass spectrometry (SPME-GC-MS) in full-scan mode for the determination of volatile organic compounds (VOC) is presented. The development of a fast and simple screening technique for the simultaneous determination of various volatiles is of great importance, because of their widespread use, frequent occurrence in forensic toxicological questions and the fact that there is often no hint on involved substances at the crime scene. To simulate a screening procedure, eight VOC with different chemical characteristics were chosen (isoflurane, halothane, hexane, chloroform, benzene, isooctane, toluene and xylene). To achieve maximum sensitivity, variables that influence the SPME process, such as type of fiber, extraction and desorption temperature and time, agitation and additives were optimized by preliminary studies and by means of a central composite design. The limits of detection and recoveries ranged from 2.9 microg/l (xylene) to 37.1 microg/l (isoflurane) and 7.9% (chloroform) to 61.5% (benzene), respectively. This procedure can be used to answer various forensic and toxicological questions. The short time taken for the whole analytical procedure may make its eventual adoption for routine analysis attractive.
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