[en] Odour identification with gas sensor arrays relies on two main parameters: the limit of detection, defined as the concentration of the analyte corresponding to the lowest detectable signal for the sensors, and the limit of resolution, defined for pair-wise comparisons of vapours, as the concentration levels below which a vapour can no longer be reliably recognised from another one on the basis of its response pattern. For real-life environmental odours, however, it is no longer possible to express such limits in "concentration" terms, because they are complex gas mixtures composed of hundreds of various compounds. The paper tries to assess both limits for odorous sources in the environment firstly by finding an equivalence of the odour concentration, expressed in odorous unit per cubic meter (ou/m3), and the concentration of a reference gas, here the ethanol, and secondly by working with a statistical metric, based on the magnitude and standard deviations along linear projections of clustered response data. The methodology is illustrated for a metal oxide gas sensor array and the odour generated by urban waste composting facilities, which is compared to the background air and to ethanol vapour.
Disciplines :
Environmental sciences & ecology
Author, co-author :
Nicolas, Jacques ; Université de Liège - ULiège > Département des sciences et gestion de l'environnement > Surveillance de l'environnement
Romain, Anne-Claude ; Université de Liège - ULiège > Département des sciences et gestion de l'environnement > Surveillance de l'environnement
Language :
English
Title :
Establishing the limit of detection and the resolution limits of odorous sources in the environment for an array of metal oxide gas sensors
Romain A.-C., Nicolas J., Andre P. In situ measurement of olfactive pollution with inorganic semiconductors: limitations due to humidity and temperature influence. Semin. Food Anal. 2:1997;283-296.
Romain A.-C., Nicolas J., Wiertz V., Maternova J., Andre P. Use of a simple tin oxide sensor array to identify five malodours collected in the field. Sens. Actuators, B Chem. 62:2000;73-79.
A.-C. Romain, J. Nicolas, J. Maternova, Identification of Several Environmental Odours with Tin Oxide Sensor Array: 3 years later, Third NOSE School and International School on Gas Sensors, Lecce, 28 May-2 June 2001.
A. Ortega, Development of Electronic Noses: Pattern Recognition Algorithms, Electronics Engineering, University of Barcelona, Barcelona, 2001, p. 344.
Zellers E.T., Park J., Hsu T., Groves W.A. Establishing a limit of recognition for a vapor sensor array. Anal. Chem. 70:1998;4191-4201.
Müller R. High electronic selectivity obtainable with nonselective chemosensors. Sens. Actuators, B. 4:1991;35-39.
Gardner J.W. Performance definition and standardization of electronic noses. Sens. Actuators, B Chem. 33:1996;60-67.
Doleman B.J., Lonergan M.C., Severin E.J., Vaid T.P., Lewis N.S. Quantitative study of the resolving power of arrays of carbon black-polymer composites in various vapor-sensing tasks. Anal. Chem. 70:1998;4177-4190.
Doleman B.J., Sanner R.D., Severin E.J., Grubbs R.H., Lewis N.S. Use of compatible polymer blends to fabricate arrays of carbon black-polymer composite vapor detectors. Anal. Chem. 70:1998;2560-2564.
Doleman B.J., Lewis N.S. Comparison of odor detection thresholds and odor discriminablities of a conducting polymer composite electronic nose versus mammalian olfaction. Sens. Actuators, B Chem. 72:2001;41-50.
Severin E.J., Doleman B.J., Lewis N.S. An investigation of the concentration dependence and response to analyte mixtures of carbon black/insulating organic polymer composite vapor detectors. Anal. Chem. 72:2000;658-668.
Goodner K.L., Dreher J.G., Rouseff R.L. The dangers of creating false classifications due to noise in electronic nose and similar multivariate analyses. Sens. Actuators, B Chem. 80:2001;261-266.
J. Nicolas, A.-C. Romain, Assessment of detection thresholds of metal oxide sensors based e-nose to the pollution emitted by odorous sources, ISOEN'02, Rome, Italy, 29 September-2 October 2002.
A.-C. Romain, J. Nicolas, M. Kuske, Monitoring the odour of compost as a process variable, in: International Symposium on Olfaction and Electronic Nose - ISOEN'03, Riga, Latvia, 26-28 June 2003.
M. Devos, F. Patte, J. Rouault, P. Laffort, L.J.V. Gemert, Standardized Human Olfactory Thresholds, IRL Press, Oxford University Press, 1990, p. 165.