Electronic nose principle

J.W. Gardner and P.N. Bartlett, Electronic Noses. Principles and Applications, Oxford University Press, Oxford, 1999. 

Refs. [i] Gardner JW, Bartlett PN (1999) Electronic noses Principles and applications. Oxford University Press, Oxford [ii] Dickinson TA, White J, Kauer JS, Walt DR (1998) Trends Biotechnol 16 250... 

Gardner, J.W. and Bartlett, P.N., Electronic noses Principles and application, Oxford... 

Towards an integrated electronic nose using conducting polymer sensors , Hatfield, J. V., Neaves, P., Hicks, P. J., Persaud, K., and Travers, P., Sensors and Actuators B, 1994, 18-19, 221 Electronic nose detects the nast nifis, Coghlan, A., New Scientist, 1994, 141 (1911), 20 Electronic noses principles and applications , Gardner, J. W. and Bartlett, P. N., OUP, Oxford, 1999. 

Bartlett P. N. and Ling-Chnng K., Condncting polymer gas sensors Part III, Sens. Actuators, 20, 287-292, 1989 Gardner J. W. and Bartlett P. N., Electronic Noses, Principles and Applications (Oxford Oxford Science Publications, 1999). 

Gardner J. W. and Bartlett P. N., Electronic Noses Principle and Applications (Oxford Oxford University Press, 1999). 

Gardner JW, Btutlett PN (1999) Electronic noses. Principles and applications. Oxford University Press, Oxford Gauglitz G (2005) Direct optical sensors principles and selected applications. Anal Bioanal Chem 381 141-155 Geistlinger H (1993) Electron theory of thin film gas sensors. Sens Actuators B 17 47-60... 

Using the principles of biological olfaction, electronic nose systems contain arrays of different types of cross-reactive vapor-sensitive sensors. While it is difficult to discriminate analytes entirely by their responses to a single type of sensor, using an array of sensors yields response patterns that can readily distinguish many different vapors. Ideally, the response mechanisms of the sensors are highly varied and encompass both physical and chemical phenomena1. 

The key principle involved in the electronic nose concept is the transfer of the total headspace of a sample to a sensor array that detects the presence of volatile compounds in the headspace and a pattern of signals is provided that are dependent on the selectivity and sensitivity of sensors and the characteristics of the volatile compounds in the headspace [2]. 

Fig. 2. The principle configuration of an electronic nose system where the analyte mixture is contacted with a chemical sensor array that produces raw data which subsequently are treated with a pattern recognition algorithm that delivers the predicted result...

Electronic noses are vapour detection systems that mimic key principles of biological olfaction [1]. The functioning principles of biological, olfactory systems do not rely upon selective interactions with specific analytes, but rather on cross-reactive receptors [2]. The receptors respond to many odours, generating unique response patterns, which serve as fingerprints for each odour. 

Work is ongoing for designing an electronic nose inspired from the biological principles detailed above. This will include the adaptation of our AL model so as to interface it with gas sensors and the development of an SVM type MB model for discriminating the binary codewords provided by the AL model. 

The first chapter reviews the basic principles of an electronic nose and explores possible ways in which the detection limit of conventional electronic nose technology can be reduced to the level required for the trace levels observed for many explosive materials. 

The principle of working which operates the electronic nose is distinctly different from that of commonly used analytical instruments (e.g. gas chromatograph). The e-nose gives an overall assessment of the volatile fraction of the foodstuff that is, in large p>art responsible for the perception of the aroma of the investigated sample, without the need to seprarate and identify the various components. All the responses of the sensors resulted from the electronic nose creates a "map" of non-sp>ecific signals that constitute the profile of the food product, also called olfactory fingerprints. 

In principle, odors may be determined by means of sample recognition with the help of arrays of gas sensors, so-called electronic noses. Unknown samples are compared with known samples. Hence, olfactometric investigations need to precede. Such a measuring device is applicable only in a specific case and has to be trained prior to use. Odor can become a controllable quality feature of a product. Samples of good quality can be made distinguishable from samples of bad quality. 

To illustrate the variance in sensor response behavior, the array was used for vapor recognition, as this is common in electronic noses. The responses of an array of eight sensors, two from each type, were used for a principle component analysis (PCA) of the vapor response. A good separation between the five test... 

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