TRANSIENT-RESPONSE OF THICK-FILM TIN OXIDE GAS-SENSORS TO MULTICOMPONENT GAS-MIXTURES

In this study we analyse the conductance transient of thick-film tin o xide sensors under a step change in a multicomponent gas mixture conce ntration. We discuss a new nonlinear diffusion model which accurately depicts experimental sensor behaviour in the low-medium gas concentrat ion range. This model allows a set of n concentration-independent para meters (tau(1)', tau(2)', ..., tau(n)') to be estimated. Each paramete r is characteristic of a species present in the n-component mixture an d varies from one sensor to another. By adjusting conductance transien t measurements of binary mixtures (ethanol, toluene and ethylbenzene) to theoretical transients, we obtained tau(i)' values. This new set of constants may give useful information for identifying the components of gas mixtures. (C) 1998 Elsevier Science S.A. All rights reserved.