Use of GC×GC for the characterization of odours in forensic applications

In forensic science, the emission of odours from objects or biological matrices is exploited for different purposes. For example, the monitoring of odours via biological or analytical detectors is used in thanatochemistry, the chemistry of death. The analysis of decomposition odour can be explored to support the localization of a missing body, a scenario encountered in urban search and rescue operations. A better understanding of the formation and evolution of decomposition odour is also of high interest to human remains detection canine handlers to improve training practices and chose appropriate training aids. Next to thanatochemistry, many other types of evidence evaluation benefit from the characterization of the volatile profile including the analysis of fire debris, chemical threat agents, explosives, and drugs. From a chemical point of view, an odour represents a complex mixture of gaseous molecules and its characterization demands for a powerful analytical technique. Especailly, in non-targeted analysis, the separation power provided by one-dimensional (1D) gas chromatography (GC) can be surpassed. Thus, a better insight is usually achieved using a multidimensional technique, such as comprehensive two-dimensional gas chromatography (GC×GC). This chapter focuses on scientific articles published between 2015 and 2020 reporting on the use of GC×GC for odour characterization in the context of forensic science. The main points are decomposition odour, volatolomic applications for profiling of human scent and illegal trade goods such as wildlife parts. Furthermore, the investigation of volatile traces of drugs and ignitable liquids in the context of arson investigations is addressed in detail. For each section, the length is proportional to the number of publications from the literature review.