Novel gas chromatographic microsystem with very large sensor arrays for advanced odour discrimination

Here we report on a new technology for electronic noses (e-noses). This combines two large sensor arrays with a micro-package that behaves similarly to a gas chromatograph column, inspired by the nature of the human olfactory mucosa. Our system comprises two silicon based chemo resistive arrays of 300 sensors with a micro-fluidic package, formed by stereo-lithography, fitted between them. In this configuration, the first sensor array provides a "spatial" response to an odour, similar to a traditional e-nose. Then, as the odour pulse travels along the column, chemical components are selectively delayed, thus the second array gives temporal information. Experiments show a time delay of up to 38 s between ethanol and toluene pulses traveling down the column. We believe that this combination of an initial sensor array, producing spatial data with a second array creating spatio-temporal data significantly enhances the ability of an e-nose to discriminate between complex odours.