Chemists from the University of Illinois have developed an artificial nose that can detect odours by changing its colour.
The nose, a dye-coated piece of paper developed by the university’s Kenneth Suslick and Neal Rakow, may be used to detect toxins, noxious gasses in chemical warfare and environmental pollutants.
When odour mollecules land on the dye they stick to a doughnut-shaped molecule called a metalloporphyrin. The subsequent reaction causes the dye to change colour and is the key to how the artificial nose works.
Suslick and Rakow call this ‘smell-seeing’ and they have built an array of spots containing different metalloporphyrins on a slip of paper.
Each spot gives a diferent colour change depending on the molecules that stick to it which enables a colour ‘fingerprint’ to be taken for an environmental sample.
A colour scanner attached to a PC takes snapshots of the samples before and after exposure to an odorous substance. Software is then used to manipulate the two samples and is able to provide an accurate comparison of the two.
Suslick believes the smell-seeing arrays could be utilised by the food and drink industry to detect favourings, additives or spoilage.
Similarly, Customs officials may use the artificail nose to detect explosives and narcotics and the pefume industry could employ it to detect fake products on the market.
The University of Illinois team have pattented the technique and are now working on a portable ‘smell-camera’ that takes ‘aroma snap-shots’.