‘Smell of death’ reveals cadaver's secrets

The research could help train sniffer dogs that are used to locate disaster victims © Shutterstock

Not many of us like to consider the complex chemical processes that begin after we die. But new research into the chemical odours released by decomposing bodies is providing forensic scientists with a powerful tool to determine how long a person has been dead, a term known as post-mortem interval (PMI).  Understanding this ‘smell of death’ also helps scientists understand how sniffer dogs discover buried disaster victims and locate clandestine graves.

An international research team used two-dimensional gas chromatography time-of-flight mass spectrometry to characterise the odours that create this smell of death:  volatile organic compounds (VOCs).  By measuring the VOCs released from pig carcasses the team identified a cocktail of several different families of molecules, including carboxylic acids, aromatics, sulfurs, alcohols, nitro compounds, as well as aldehydes and ketones. The combination and quantities of these VOCs change as a function of time as a cadaver goes through different stages of decomposition.

Author Jean-François Focant from the University of Liege, Belgium, tells Chemistry World:  ‘The use of state-of-the-art multi-dimensional techniques has allowed us to drastically improve our understanding of the VOC mixtures released during cadaveric decomposition. An odour fingerprint can be created for each stage of decomposition and possibly be used as an additional tool to estimate the PMI.’

Current PMI estimation is limited to assessing things like body cooling, how advanced decomposition is and the size of insects that have colonised the body. However, these do not always give an accurate answer. ‘Charting the changes to VOCs won’t provide a 100% reliable way of estimating PMI but it might improve the situation enormously,’ explains Anna Williams, a forensic anthropologist at the University of Huddersfield, UK.

The research could also help with the training of ‘human remains detection canines’. ‘We know very little about what compounds or combinations of compounds are recognised by sniffer dogs,’ says  Williams. ‘Understanding this helps to improve their work in the field and with training aids. However, research on pigs as analogues for humans is compromised from the start. A human taphonomy facility (where the decomposition of human remains are studied) would boost forensic research.’

The development of a VOC profile for decomposing bodies should help scientists working to create an electronic nose, which are hardier than dogs and do not need costly training and upkeep. Sniffer dogs are more adaptable than their e-nose counterparts, however, and by entering dangerous places alone they help to keep their handlers safe. ‘Several groups are working on e-noses at the moment,’ Focant says, ‘but we are not sure if this technology will ever make sniffer dogs obsolete.’

Related Content

Spectrometry to the rescue!

15 January 2013 Research

news image

Ion mobility spectrometry could replace sniffer dogs hunting for survivors in the wake of natural disasters


1 August 2012 Podcast | Compounds

news image

This week's podcast is about putrescine

Most Read

Quintuple bond activates small stable molecules

19 September 2014 Research

news image

Exotic complexes suggest route to synthetic feedstock

Computer simulations point to formamide as prebiotic intermediate in ‘Miller’ mixtures

16 September 2014 News and Analysis

news image

Electric field may have provided more than just energy for primordial chemistry

Most Commented

US genomics lead being lost to China

17 September 2014 News and Analysis

news image

NIH senior leaders are sounding the alarm bells, saying the US's pre-eminence in genomics research is under threat

The trouble with boycotts

29 August 2014 Critical Point

news image

Cutting academic ties with a censured state can do more harm than good, says Mark Peplow