Sniffer dogs have helped the authorities in tracking down all manner of scents, from dead bodies to explosives, and a new study published in the journal Forensic Chemistry has revealed that they can sniff out gasoline in quantities as small as one-billionth of a teaspoon. The findings highlight how effective the employment of pooches can be in arson investigations.
"During an arson investigation, a dog may be used to identify debris that contains traces of ignitable liquids – which could support a hypothesis that a fire was the result of arson," explained lead author Robin Abel, a graduate student in the Department of Chemistry, in a statement. "Of course, a dog cannot give testimony in court, so debris from where the dog indicated must be taken back to the laboratory and analyzed. This estimate provides a target for forensic labs when processing evidence flagged by detection dogs at sites of potential arson."
The study saw one dog and its handlers attempt to detect a variety of flammable liquids, while another sniffer dog was tested for detecting specifically gasoline. The findings revealed that the dog tasked with detecting a variety of flammable liquids performed well detecting all accelerants. However, the dog trained on gasoline alone was not able to generalize to other accelerants at extremely low concentrations, but it was able to detect traces of the liquid to a minute degree (one billionth of a teaspoon).
"The dogs in this study were able to detect down to one billionth of a teaspoon – or 5 pL – of gasoline," said James Harynuk, an associate professor of chemistry and supervisor on the study. "Their noses are incredibly sensitive."
The admittedly small study also facilitated the development of a novel protocol, which can be employed to generate suitable ultra-clean substrates necessary to test the skills of future accelerant-detection dogs in order to see if they can successfully detect trace levels of accelerants.
"In this field, it is well-known that dogs are more sensitive than conventional laboratory tests," said Harynuk. "There have been many cases where a dog will flag debris that then tests negative in the lab. In order for us to improve laboratory techniques so that they can match the performance of the dogs, we must first assess the dogs. This work gives us a very challenging target to meet for our laboratory methods."