A
group of U.S. researchers have developed an artifical nose that
detects scent better than the real thing.
The technology, called
"smell-seeing," detects the colour changes that occur when chemicals
are exposed to substances that emit odors.
The technique uses an array of vapour-sensitive dyes called
metalloporphyrins — molecules that bind metal atoms.
Metalloporphyrins are closely related to hemoglobin, the red pigment
in blood, and chlorophyll, the green pigment in plants.
The array is made by marking a piece of paper, plastic or glass
with a series of tiny dots using differnet dyes.
An ordinary flatbed scanner or an electronic camera is used to
scan the array before and after it is exposed to an odor-producing
substance. The before image is subtracted from the after image to
get a pattern that shows the colour change.
Scientist can then use the pattern to identify what chemical
compounds were added by comparing the pattern to a library of colour
fingerprints, therefore enabling them to indentify the substance the
array was exposed to by its scent.
Kenneth Suslick and Neal Rakow, both chemists at the University
of Illinois, say their artifical nose is 10 to 100 times more
sensitive than the human nose for many compounds.
The potential for the technology is huge. Some possible
applications include food companies using the technology to detect
flavourings or spoilage, police using it to detect illegal drugs, or
safety inspectors using it to detect and monitor poisons or toxins
in workplaces that use dangerous chemicals.
The research appears in the latest issue of Nature
magazine.
