colorimeter
Researchers at the University of Illinois, Urbana-Champaign have developed a way to compare aromas visually using specially developed inks.
Kenneth Suslick and his colleagues used tiny squares of polymer film that hold 36 drops of carefully designed dyes. These pigments change colour when exposed to various chemicals. The result is a cheap system for detecting very low concentrations of gaseous compounds. The cards can be used like a physicist's radiation dose badge to alert lab workers when they have been exposed to toxic gases.
As shown above, the cards can be used to give each…