THE ZNOSE: A NEW ELECTRONIC NOSE TECHNOLOGY FOR ANALYTICAL EXPLORATION OF THE CHEMICAL WORLD WHICH SURROUNDS US ALL

Life is based upon a complex mix of organic and inorganic chemical processes. In fact the importance of geochemical and industrial processes responsible for changes to our planetary atmosphere are only now being acknowledged by the general population. The importance and relevance of vapor chemistry in ordinary life experiences has been blunted by our inability to ‘see’ or quantify these chemicals, which traditionally has been the domain of laboratory chemists. The zNose™ is changing this method.

Faster qualitative and quantitative analyses are becoming a necessity in today's environment. However, early electronic noses based upon sensor arrays to mimic the human olfactory process have proved unsuccessful because they were unable to link the olfactory experience with odor chemistry. The answer to this problem is the zNose™.

The zNose™, is rapidly being accepted as a measurement tool for quality control in commercial applications as well as on-site monitoring of the chemical environment. The zNose™ is able to speciate and quantify the individual chemicals in 10 seconds with part per billion sensitivity using only a single solid-state sensor. Simultaneously, it can produce high-resolution visual olfactory images, called VaporPrints, enabling humans to visually recognize aromas and individual chemicals. Performing analytical chemical measurements quickly and accurately in the field may prove as useful in geochemical applications as it is in commercial fields. Now, you can ‘see’ and quantify the hydrocarbons which surround us all.

In the zNose™, individual analyte peak half-widths are measured in milliseconds and vapor chemistry is analyzed with a temperature-controlled quartz crystal in seconds. The surface of the quartz crystal plays host to a high-Q surface acoustic wave (SAW) interferometer which reflects and focuses a high frequency ultrasonic wave to produce a frequency as stable as an atomic clock. Chemicals deposited on the crystal change the velocity of the acoustic waves and produces a frequency difference proportional to the chemical concentration.

This paper explains the theory behind the development of the zNose™ and presents many real examples. The ability to now ‘see’ the chemistry which surrounds us really is like having an eye in the kingdom of the blind.