Characterizing decomposition odor from soil and adipocere samples at a death scene using HS-SPME-GC×GC-HRTOFMS

Abstract

Using decomposition odor as forensic evidence remains highly controversial despite well-established gas chromatography – mass spectrometry (GC–MS) techniques. Although extensive research characterizing decomposition odor has been conducted, its use in court has been publicly debated due to its admission in the trial The State of Florida vs. Casey Marie Anthony, largely due to the perception that it was too untested. Since this case, a shift from conventional GC–MS to comprehensive two-dimensional gas chromatography – mass spectrometry (GC×GC–MS) has occurred for analyzing decomposition odor. It has become apparent that GC×GC coupled with time-of-flight mass spectrometry (TOFMS), and high-resolution TOFMS (HRTOFMS), is valuable for the analysis of volatile organic compounds (VOCs) from decomposing cadavers as a higher number of VOCs can be detected and identified confidently. This was the first application of GC×GC-HRTOFMS analyzing decomposition VOCs in a forensic case. From a decomposition site, soil from different locations around the body, and adipocere samples were collected. The main objective was to investigate the heterogeneity of the samples using GC×GC–MS. Future challenges anticipated in case scenarios were also interpreted using the generated data. VOCs identified in the soil samples reflected those identified in previous studies, while the profile of adipocere was demonstrated for the first time by GC×GC-HRTOFMS and was dominated by volatile carboxylic acids and acid esters. The power of GC×GC images in court testimony was considered to be of high potential. This case study will strengthen the reliability and evidentiary value of decomposition odor as a valid forensic field.