A Comparison of One-Dimensional and Comprehensive Two-Dimensional Gas Chromatography for Decomposition Odour Profiling Using Inter-Year Replicate Field Trials
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Decomposition odour analysis involves the chemical profiling of volatile organic compounds produced by decomposing remains. This is important for areas of forensic science that rely on the detection of decomposition odour such as insect attraction to carrion, positive alerts of cadaver dogs to decomposing remains, and the development of field instrumentation for search and recovery procedures. Traditionally decomposition odour analysis has been performed using gas chromatography–quadrupole mass spectrometry (GC–qMS); however, the use of comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC×GC–TOFMS) is rapidly becoming more prevalent. The objective of this study was to compare GC–qMS and GC×GC–TOFMS for decomposition odour profiling based on inter-year replicate field studies using decomposing porcine remains. The increased peak capacity, sensitivity and selectivity afforded by GC×GC–TOFMS allowed peak co-elutions, chromatographic artefacts, and dynamic range to be more easily addressed and managed. Furthermore, the software associated with GC×GC–TOFMS provided several additional benefits including improved peak alignment between samples and increased consistency of reported results, overall allowing for additional statistical tests to be applied following data processing. Future GC–qMS results could be improved by implementing some of these software-associated procedures, potentially reducing the magnitude of variation observed between GC–qMS and GC×GC–TOFMS studies. One-dimensional GC analysis may also benefit substantially from coupling with TOFMS detection to provide an indirect increase in peak capacity using deconvolution. However, the wealth of information gained by using GC×GC–TOFMS in decomposition odour profiling is undoubtedly an asset in this field of research.
KeywordsGC–qMS GC×GC–TOFMS Forensic chemistry Volatile organic compounds Thermal desorption Non-target analysis
The authors wish to thank all research group members and extended contacts who have contributed to the planning and execution of field work over the past several years: Maiken Ueland, Kate Trebilcock, LaTara Rust, Amanda Troobnikoff, Laura McGrath, Rebecca Buis, Assoc. Prof. Barbara Stuart, Dr. Paul Thomas, Chris Watson and Robert Chatterton. Clare Sullivan is gratefully acknowledged for her assistance with GC–qMS samples. The authors also wish to thank laboratory technical staff, Dr. David Bishop and Dr. Ronald Shimmon, for their ongoing support. Finally, SGE Analytical Science is recognised for donating research supplies while the Australian Research Council (ARC) and the University of Technology, Sydney (UTS) are acknowledged for providing financial support for this work.
Conflict of interest
The authors declare that they have no conflict of interest.
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