Statistics show that there was a 12% increase in missing persons’ incidents in the UK between 2014 and 2019. Approximately 50% of these missing individuals are found within 24 hours, and on average a large number will be deceased. Land-based searches are relatively straight forward, however searches in aquatic environments can be significantly more complex and often require the deployment of significant manpower. As a result, there is a desire to use technology to increase the efficiency of these searches. The use of instrumentation to detect a ‘chemical fingerprint’ of decomposition in water would have significant potential to achieve this aim.The focus of this work was on the chemical profile of water influenced by decomposition, and the effects different environmental factors have on this profile via metabonomic analysis. Liquid chromatography-mass spectrometry was combined with quality control measures, multivariate and statistical analysis to investigate these changes.Initial studies focused on improving sample preparation, to allow maximum output from the instrument. It was discovered that pre-concentrating a 1 L sample of water exposed to decomposing remains using solid-phase extraction was the most effective way to capture and concentrate as many compounds as possible for this non-targeted research.An investigation into species differentiation based on the chemical signature of water containing rabbit or duck remains was able to produce three positive identified markers (cadaverine, leucine and creatinine) that were significantly different between species. These significant differences are based on the change in abundance and behaviours of these markers over a series of time points, and whether these patterns are specific to a particular species or not. Furthermore, it was discovered that the nature of the water (moving and still water) influenced the speed in which these chemical processes occurred during decomposition. It was also evident that the quantity of compounds in a sample taken from still water was much higher. The effects of temperature were investigated throughout this work. It was clear that although lower temperatures did affect the speed of decomposition and the amount of significantly different features in each sample compared to summer, it is important to note that chemical decomposition was still progressing, albeit slowly. These lab-based methods were also successfully implemented to analyse samples obtained from an experiment with human subjects.These preliminary experiments have highlighted the potential of using metabonomic analysis to monitor non or semi volatile compounds leaching into the water as a result of decomposition. These initial developments could be applied further to assist the forensic science community
