As any classic murder mystery or spy thriller will tell you, cyanide is a poison that acts quickly. Once exposed to it, a person can die within 30 minutes. Unfortunately for people who think they might have encountered it, the standard test for determining exposure takes 24 hours. Now, however, a scientist at South Dakota State University has developed a sensor that detects cyanide within a blood sample in just 70 seconds.

The prototype device was created by Associate Professor Brian Logue.

Once a blood or water sample is put in it, an acid in the device causes any cyanide present to be converted into a gas. That gas is subsequently trapped in a base material. The contained cyanide then reacts with another chemical agent, which causes it to fluoresce when exposed to light. By measuring the intensity of that fluorescence, the concentration can be deduced.

Associate Professor Brian Logue (right) watches as postdoctoral researcher Randy Jackson fills the cyanide sensor cartridge with chemical reagents (Photo: SDSU)

In tests on rabbits, the sensor was 100 percent accurate at detecting cyanide exposure, even at concentrations that were 200 times lower than the lethal amount.

Plans now call for testing on larger animals, along with miniaturization and FDA approval of the device. Logue would also like to get its processing time down to under one minute, plus he hopes to find a way of detecting cyanide in saliva samples, as the poison usually enters the body through the mouth or nose.

And in case you were wondering, the sensor isn't intended for use by spies. Instead, it's aimed more at people like firefighters, who can be exposed to cyanide while working at industrial fires. Currently, if cyanide exposure is suspected, they must simply be treated for it without knowing if such exposure actually occurred.

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