Breath test could identify trapped survivors in disaster zones

A team of atmospheric chemists has published a study suggesting we hunt down trapped survivors in disaster zones by testing for chemicals found on the human breath.

The researchers, led by Wolfgang Vautz of Germany's Leibniz Institute for Analytical Sciences, developed the technique using a combination of rapid gas chromatography and ion mobility spectrometry, which they believe could be a portable and quick alternative to the use of animals in the field -- while dogs sniff out people with their finely-tuned senses, they will often be unable to distinguish between an individual who is dead or alive. Of course emergency teams will be working to retrieve all people from debris in disaster zones, but every second is important when it comes to getting to the survivors first.

This new technique tunes into the chemicals a survivor will exhale. The idea is that a tube is fed deep into rubble to collect air samples. These are then run through a gas chromatograph to separate the different chemicals in the vapour. The resulting gases are then fed through a portable ion mobility spectrometer, which ionises the chemicals before hurling them through a chamber -- the team can identify what the chemical is by recording how long it takes for them to pass through the chamber.

Carrying out a field test, Vautz and his team asked ten volunteers to spend time in a confined space that replicated a void within debris. With those volunteers trapped in for six hours at a time, the team would extract an 8ml air sample every 20 minutes. After running the samples through the gas chromatographer, then breaking down the ions, it took the team just three minutes to compare the results against a database and identify 12 chemicals commonly found on human breath, including acetone and benzaldehyde. All ten volunteers were successfully identified. In another experiment, the team was able to identify the presence of a person in a 25 square metre cubed room after they had spent 30 minutes in it, meaning the process is sensitive enough to pick those 12 metabolites out.

Although the process appears to be a helpful tool, with rescue workers focusing purely on finding high levels of those 12 chemicals, it will no doubt have its practical problems. Feeding the tube through a chaotic mass of debris will need a time-consuming trial and error approach to get it through blockages. The whole process would also need simplifying so that rescue workers rather than trained chemists can carry out the work -- they'd need a user-friendly version of the analysis equipment. Nevertheless, it's promising to see progress in a field where we still rely largely on the senses of both humans and animals.

Friday 11 January 2013

http://www.wired.co.uk/news/archive/2013-01/11/rescue-survivors-breath-test