Hum Posted August 10, 2010 Share Posted August 10, 2010 A "sniffer tube" could replace dogs in the arsenal of tools to locate hidden graves, say researchers. A new technique uses a long tube to quickly sample the air above suspected gravesites. The specially coated tube can spot tiny amounts of a chemical linked to the breakdown of animal remains, up to months after the remains are buried. The research is published in Forensic Science International and highlighted in New Scientist magazine. The task is to outperform the premier detector of hidden explosives, drugs, or humans alive or dead: the sniffer dog. But as much as dogs can be trained, it remains unclear what exactly they perceive. "We're not really sure what the dogs are sniffing or what they're focusing on," said Tom Bruno of the National Institute of Standards and Technology (Nist) in the US. At the heart of the approach is the use of a long tube lined with two materials: alumina, a porous but tough material that soaks up molecules from the air, and ninhydrin, a molecule that binds both to alumina and to the clues indicating a hidden grave. Almost all animal tissue is made up of proteins, which after death break down into constituent parts, some of which end up free in the air. In mammals, the structure of many of these decomposition products - with evocative names such as cadaverine - is known. When these products encounter ninhydrin, a particular bond is formed - a bond that absorbs light of a particular colour. At one end of the tube is a source of ultraviolet light and at the other a detector. The more decomposition products that settle in the tube, the more light gets absorbed along the way; the light level is then an indirect measure of the presence of decomposing flesh. more Link to comment Share on other sites More sharing options...
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