Electro-mass olfactory multi-sensor (EMMS)

For an olfactory sensor or electronic nose, the task is not only to detect the object concentration, but also to recognize it. It is well known that a ll the elements can be identified by their charge to mass ratio e(+)/m. We tried to imitate this principle for molecular recognition. Two kinds of sen sors are used simultaneously in testing. One is quartz crystal microbalance (QCM) for detecting the change in mass, the other is interdigital electrod e (IE) for detecting the change in conduction, as an electro-mass multi-sen sor (EMMS). in this paper, the principle and the feasibility of this method are discussed. The preliminary results on the recognition of alcohol by EM MS coated with lipids are presented. Meanwhile, the multi-sensor can also b e used as an instrument for research on some physico-chemistry problems. Th e change in conduction of coated membrane caused by one absorbed molecule i s reported. It is found that when a QCM is coated with membrane, it still o beys the relationship Delta F (frequency change of QCM) = K Delta m (mass c hange of absorbed substance) and the proportional coefficient, K, depends n ot only on quartz properties but also on membrane characteristics as well. (C) 2000 Elsevier Science S.A. All rights reserved.