Sniffing out fakes

A test for smells that can distinguish between real and counterfeit perfumes
has been developed by chemists at the University of Illinois. To make the
sensor, Kenneth Suslick impregnated small teflon discs with 24 compounds called
metalloporphyrins, which contain metal ions. “These are really colourful
compounds,” says Suslick. Because gases cause specific colour changes in each
metalloporphyrin, smelly gases can be identified by the colours on the discs.
“It’s like a litmus test for smells,” says Suslick.