An electronic nose employing dual-channel odour separation columns with large chemosensor arrays for advanced odour discrimination

Here we report on an improved concept for electronic noses (e-noses) that combines three large chemosensor arrays (300 resistive elements per array) with two micro-packages, each containing a column inspired by our study of the human olfactory mucosa and nasal cavity. In this novel system, a sample odour passes over the first chemoresistive array giving "spatial" response data, equivalent to a traditional sensor-based e-nose. The odour is then divided evenly and passes through two further micro-packages (and thus columns) simultaneously. As the odour pulse travels along these columns chemical components within it are selectively delayed, thus the second and third array, placed after the micro-packages, provide both temporal retentive and spatial information. This combination of a front-end sensor array with back-end second and third arrays, coupled with appropriate pattern analysis algorithms, is shown to enhance significantly the system's ability to discriminate between complex odours. The columns were coated with non-polar and polar compounds to maximise the discrimination ability of the system. We believe that this combination of an initial sensor array, creating spatial data with the spatio-temporal data from the second array significantly enhances the ability of e-noses to discriminate complex odours.