Conducting polymers, electronic nose technology

These electronic noses are for specific purposes and there is presently no universal nose that can solve all odour sensing problems. There is thus a need to develop specific electronic nose technology appropriate for the application. This means developing sensors, materials and appropriate pattern-recognition methods. There is thus a wide scope for the development of an artificial nose, based on conducting polymers, that can mimic the human nose. 

Table 3. Some commercial companies that manufactured sensor-based electronic noses and related instruments in 2003. Key to sensor technologies MOS - metal oxide sensor, CP -conducting polymer, QMB - quartz crystal microhalance, FET - field effect transistor, SAW - surface acoustic wave key to analytical instruments MS - mass spectrometry, GC - gas chromatography, IMC - ion mobility cell...

Electronic noses have also been used to analyze meat flavor. Warmed-over flavor (WOE) in beef was studied by 32 conducting polymer sensors [30]. The meat was processed by vacuum cook-in-bag/tray technology (VCT) and stored in a refrigerator. The VCT process involves treatment at 50°C for 390 minutes. The authors indicated that electronic noses can be readily utilized for WOE identification in beef and can be a useful addition to sensory analysis. 

Eitzgeiuld FT, Tiemey LM Jr (1982) The bedside Sherlock Holmes. West J Med 137 169-175 Fleet B, Gunasingham H (1992) Electrochemical sensors for monitoring environmental pollutants. Talanta 39 1449-1457 Flueckiger J, Ko FK, Cheung KC (2009) Microfabricated formaldehyde gas sensors. Sensors 9 9196—9215 Fontes J (2005) Humidity sensors. In Wilson JS (ed) Sensor technology handbook. Elsevier, Oxford, pp 271-284 Freund MS, Lewis NS (1995) A chemically diverse conducting polymer-based electronic nose. Proc Natl Acad Sci USA 92 2652-2656... 

Sensorics, also known as the electronic nose, represent another interesting technology where polymers are used because synthetic chemosensors can only detect a molecule when it is dissolved in a polymeric layer present in the sensor. The technology involves the use of a quartz crystal microbalance device to detect by volume and analyse surface waves on piezoelectric materials. Swelling detection on the basis of variations in conductivity also forms part of the technology. The role of polymers in this technology was discussed in an article by Banhegyi [3]. 

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