Developing a method for the collection and analysis of burnt remains for the detection and identification of ignitable liquid residues using body bags, dynamic headspace sampling, and TD-GC×GC-TOFMS

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. In cases of suspected arson, a body may be intentionally burnt to cause loss of life, dispose of remains, or conceal identification. A primary focus of a fire investigation, particularly involving human remains, is to establish the cause of the fire; this often includes the forensic analysis of fire debris for the detection of ignitable liquid residues (ILRs). Commercial containers for the collection of fire debris evidence include metal cans, glass jars, and polymer/nylon bags of limited size. This presents a complication in cases where the fire debris consists of an intact, or partially intact, human cadaver. This study proposed the use of a body bag as an alternative sampling container. A method was developed and tested for the collection and analysis of ILRs from burnt porcine remains contained within a body bag using dynamic headspace sampling (using an Easy-VOC™ hand-held manually operated grab-sampler and stainless steel sorbent tubes containing Tenax TA) followed by thermal desorption comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (TD-GC×GC-TOFMS). The results demonstrated that a body bag containing remains burnt with gasoline tested positive for the presence of gasoline, while blank body bag controls and a body bag containing remains burnt without gasoline tested negative. The proposed method permits the collection of headspace samples from burnt remains before the remains are removed from the crime scene, limiting the potential for contamination and the loss of volatiles during transit and storage

Achieving a near-theoretical maximum in peak capacity gain for the forensic analysis of ignitable liquids using GC×GC-TOFMS

© 2016 by the authors; licensee MDPI, Basel, Switzerland. At present, gas chromatography–quadrupole mass spectrometry (GC-qMS) is considered the gold standard amongst analytical techniques for fire debris analysis in forensic laboratories worldwide, specifically for the detection and classification of ignitable liquids. Due to the highly complex and unpredictable nature of fire debris, traditional one-dimensional GC-qMS often produces chromatograms that display an unresolved complex mixture containing only trace levels of the ignitable liquid among numerous background pyrolysis products that interfere with pattern recognition necessary to verify the presence and identification of the ignitable liquid. To combat these challenges, this study presents a method optimized to achieve a near-theoretical maximum in peak capacity gain using comprehensive two-dimensional gas chromatography (GC×GC) coupled to time-of-flight mass spectrometry (TOFMS) for the forensic analysis of petroleum-based ignitable liquids. An overall peak capacity gain of ~9.3 was achieved, which is only ~17% below the system’s theoretical maximum of ~11.2. In addition, through the preservation of efficient separation in the first dimension and optimal stationary phase selection in the second dimension, the presented method demonstrated improved resolution, enhanced sensitivity, increased peak detectability and structured chromatograms well-suited for the rapid classification of ignitable liquids. As a result, the method generated extremely detailed fingerprints of petroleum-based ignitable liquids including gasoline, kerosene, mineral spirits and diesel fuel. The resultant data was also shown to be amenable to chromatographic alignment and multivariate statistical analysis for future evaluation of chemometric models for the rapid, objective and automated classification of ignitable liquids in fire debris extracts

Establishing the volatile profile of pig carcasses as analogues for human decomposition during the early postmortem period

© 2016 The Authors. Following a mass disaster, it is important that victims are rapidly located as the chances of survival decrease greatly after approximately 48 h. Urban search and rescue (USAR) teams may use a range of tools to assist their efforts but detector dogs still remain one of the most effective search tools to locate victims of mass disasters. USAR teams can choose to deploy human scent dogs (trained to locate living victims) or human remains detection (HRD) dogs (trained to locate deceased victims). However, little is known about the variation between live human scent and postmortem human remains scent and the timeframe during which one type of scent transitions to the other. The aim of the current study was to measure the change in the scent profile of human decomposition analogues during the first 72 h postmortem by measuring the volatile organic compounds (VOCs) that comprise the odour. Three pig carcasses (Sus scrofa domesticus L.) were placed on a soil surface and allowed to decompose under natural conditions. Decomposition odour was sampled frequently up to 75 h postmortem and analysed using comprehensive two-dimensional gas chromatography - time-of-flight mass spectrometry (GC×GC-TOFMS). A total of 105 postmortem VOCs were identified during the early postmortem period. The VOC profile during the early postmortem period was highly dynamic, changing both hourly and daily. A transition period was observed after 43 h postmortem, where the VOC profile appeared to shift from a distinct antemortem odour to a more generalised postmortem odour. These findings are important in informing USAR teams and their use of detector dogs for disaster victim recovery

A comparison of human and pig decomposition rates and odour profiles in an Australian environment

© 2018, © 2018 Australian Academy of Forensic Sciences. Cadaver-detection dogs are trained to locate victim remains; however, their training is challenging owing to limited access to human remains. Animal analogues, such as pigs, are typically used as alternative training aids. This project aimed to compare the visual decomposition and volatile organic compound (VOC) profile of human and pig remains in an Australian environment, to determine the suitability of pig remains as human odour analogues for cadaver-detection dog training. Four human cadavers and four pig carcasses were placed in an outdoor environment at the Australian Facility for Taphonomic Experimental Research (AFTER) across two seasons. Decomposition was monitored progressively in summer and winter. VOCs were collected onto sorbent tubes and analysed using comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry. Visual observations highlighted the differences in decomposition rates, with pig remains progressing through all stages of decomposition, and human remains undergoing differential decomposition and mummification. Chemical and statistical analysis highlighted variations in the composition and abundance of VOCs over time between the odour profiles. This study concluded that the visual decomposition and VOC profile of pig and human remains was dissimilar. However, in cooler conditions the results from each species became more comparable, especially during the early stages of decomposition

In vitro volatile organic compound profiling using GCGC-TOFMS to differentiate bacteria associated with lung infections: A proof-of-concept study

© 2016 IOP Publishing Ltd. Chronic pulmonary infections are the principal cause of morbidity and mortality in individuals with cystic fibrosis (CF). Due to the polymicrobial nature of these infections, the identification of the particular bacterial species responsible is an essential step in diagnosis and treatment. Current diagnostic procedures are time-consuming, and can also be expensive, invasive and unpleasant in the absence of spontaneously expectorated sputum. The development of a rapid, non-invasive methodology capable of diagnosing and monitoring early bacterial infection is desired. Future visions of real-time, in situ diagnosis via exhaled breath testing rely on the differentiation of bacteria based on their volatile metabolites. The objective of this proof-of-concept study was to investigate whether a range of CF-associated bacterial species (i.e. Pseudomonas aeruginosa, Burkholderia cenocepacia, Haemophilus influenzae, Stenotrophomonas maltophilia, Streptococcus pneumoniae and Streptococcus milleri) could be differentiated based on their in vitro volatile metabolomic profiles. Headspace samples were collected using solid phase microextraction (SPME), analyzed using comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GCGC-TOFMS) and evaluated using principal component analysis (PCA) in order to assess the multivariate structure of the data. Although it was not possible to effectively differentiate all six bacteria using this method, the results revealed that the presence of a particular pattern of VOCs (rather than a single VOC biomarker) is necessary for bacterial species identification. The particular pattern of VOCs was found to be dependent upon the bacterial growth phase (e.g. logarithmic versus stationary) and sample storage conditions (e.g. short-term versus long-term storage at -18 °C). Future studies of CF-associated bacteria and exhaled breath condensate will benefit from the approaches presented in this study and further facilitate the production of diagnostic tools for the early detection of bacterial lung infections

Comparison of the decomposition VOC profile during winter and summer in a moist, mid-latitude (Cfb) climate

© 2014 Forbes et al. The investigation of volatile organic compounds (VOCs) associated with decomposition is an emerging field in forensic taphonomy due to their importance in locating human remains using biological detectors such as insects and canines. A consistent decomposition VOC profile has not yet been elucidated due to the intrinsic impact of the environment on the decomposition process in different climatic zones. The study of decomposition VOCs has typically occurred during the warmer months to enable chemical profiling of all decomposition stages. The present study investigated the decomposition VOC profile in air during both warmer and cooler months in a moist, mid-latitude (Cfb) climate as decomposition occurs year-round in this environment. Pig carcasses (Sus scrofa domesticus L.) were placed on a soil surface to decompose naturally and their VOC profile was monitored during the winter and summer months. Corresponding control sites were also monitored to determine the natural VOC profile of the surrounding soil and vegetation. VOC samples were collected onto sorbent tubes and analyzed using comprehensive two-dimensional gas chromatography - time-of-flight mass spectrometry (GC×GC-TOFMS). The summer months were characterized by higher temperatures and solar radiation, greater rainfall accumulation, and comparable humidity when compared to the winter months. The rate of decomposition was faster and the number and abundance of VOCs was proportionally higher in summer. However, a similar trend was observed in winter and summer demonstrating a rapid increase in VOC abundance during active decay with a second increase in abundance occurring later in the decomposition process. Sulfur-containing compounds, alcohols and ketones represented the most abundant classes of compounds in both seasons, although almost all 10 compound classes identified contributed to discriminating the stages of decomposition throughout both seasons. The advantages of GC×GC-TOFMS were demonstrated for detecting and identifying trace levels of VOCs, particularly ethers, which are rarely reported as decomposition VOCs. Copyright

Forensic Science: Current State and Perspective by a Group of Early Career Researchers

© 2016, Springer Science+Business Media Dordrecht. Forensic science and its influence on policing and the criminal justice system have increased since the beginning of the twentieth century. While the philosophies of the forensic science pioneers remain the pillar of modern practice, rapid advances in technology and the underpinning sciences have seen an explosion in the number of disciplines and tools. Consequently, the way in which we exploit and interpret the remnant of criminal activity are adapting to this changing environment. In order to best exploit the trace, an interdisciplinary approach to both research and investigation is required. In this paper, nine postdoctoral research fellows from a multidisciplinary team discuss their vision for the future of forensic science at the crime scene, in the laboratory and beyond. This paper does not pretend to be exhaustive of all fields of forensic science, but describes a portion of the postdoctoral fellows’ interests and skills

The analysis of textiles associated with decomposing remains as a natural training aid for cadaver-detection dogs

© 2017 Elsevier B.V. Cadaver-detection dogs are employed by law enforcement agencies to locate human remains in cases of missing persons, suspected homicides and following natural or man-made disasters. The ability of cadaver-detection dogs to locate human remains relies heavily on the use of effective and reliable training aids. Cadaver-detection dogs may be trained using a variety of materials ranging from natural scent sources (e.g. flesh, bone, blood or decomposition soil) to synthetic materials (e.g. Pseudo™ Scents). Commercially available synthetic scents often have an overly simplistic chemical composition that is inconsistent with decomposition odour. Therefore, natural scent sources are typically considered to be the most effective training aids; however, there is concern that using individual tissue types as natural training aids may not be indicative of the scent of an intact human cadaver. The objective of this work was to determine how well textiles associated with decomposing remains retain and mimic the odour of natural training aids. To test this, the chemical odour profile of textile samples collected from decomposing porcine remains that were buried clothed in 100% cotton t-shirts was examined. Throughout various stages of decomposition, the pig carcasses were exhumed and cotton samples were obtained. The volatile organic compound (VOC) profile of the textiles was collected using headspace solid phase microextraction (HS-SPME) and analysed using comprehensive two-dimensional gas chromatography – time-of-flight mass spectrometry (GC×GC-TOFMS). This study provides evidence that textiles associated with decomposing remains may represent a useful natural training aid with a VOC profile reflective of a large subset of cadaveric decomposition odour. The odour profile is dynamic and changes over time suggesting that obtaining textiles from different postmortem intervals would be useful for providing training aids that represent the full spectrum of decomposition odour that cadaver-detection dogs may encounter during a search. This information is particularly beneficial for law enforcement agencies searching for effective and reliable cadaver-detection dog training aids

The influence of ageing and surface type on the odour profile of blood-detection dog training aids

© 2016, Springer-Verlag Berlin Heidelberg. Cadaver-detection dogs are a preferred search tool utilised by law enforcement agencies for the purposes of locating victim remains due to their efficiency and minimal disturbance to the crime scene. In Australia, a specific group of these canines are blood-detection dogs, which are trained to detect and locate blood evidence and search potential crime scenes in cases where a cadaver may not be present. Their role sometimes requires searches to be carried out after considerable time has passed since the crime occurred, and this is important for developing effective training protocols. This study aimed to investigate the volatile organic compounds (VOCs) produced from fresh and aged human blood on various surfaces. Solid phase microextraction (SPME) was used to extract VOCs from the headspace of dried blood samples aged and sampled periodically over 12 months from a non-porous (i.e. aluminium) and porous (i.e. cotton) surface. Samples were analysed using comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC×GC-TOFMS). Fresh blood produced distinctively different VOC patterns compared to blood aged longer than 1 week with the overall profile differing between the two surface types, and a large subset of the VOC profile found to be responsible for these differences. When analysing the various functional groups present in the samples, a common pattern between ages and surface types was observed with no specific chemical class dominating the overall profile. The results highlight the importance of evaluating training aids for scent-detection canines to ensure the greatest efficacy during training and subsequently at crime scene searches

Investigating the Sensitivity of Cadaver- Detection Dogs to Aged, Diluted Decomposition Fluid

Cadaver-detection dogs (also known as human remains detection dogs) are used worldwide to locate deceased victims and human remains. Ethical restrictions often prevent the dog handlers from using cadavers as training aids, resulting in a reliance on pseudo-scents or human tissues, such as blood, bone, and decomposition fluid. Often these aids must be re-used many times because of the difficulty in obtaining new materials. The aim of this study was to investigate the dogs' sensitivity to aged human decomposition fluid samples that are used as a training aid. Human decomposition fluid was collected and serially diluted to 1 part-per-trillion (10u) and aged up to two years. The samples were presented throughout the aging process to three police accredited cadaver-detectior. dog teams under standard indoor training conditions. The dogs were capable of detecting the oldest and lowest dilution levels of decomposition fluid samples. Ongoing training to retain this level of sensitivity is recommended. The results of these trials indicate human decomposition fluid is a valid training aid for cadaver-detection dogs