Gas species and concentration detecting apparatus|results in concentration dependent mapping in which it is easy to visually distinguish one point from another on the basis of concentration

Concentration sensitive method for analysis of several outputs from a chemical sensing device, comprises (a) normalising the several outputs; (b) calculating at least one intensity output, the intensity out being related to the absolute magnitude of at least one of the outputs; and (c) performing a cluster analysis of the several normalised outputs and the intensity output(s).USE - Intensity data in cluster analysis informs about chemical concentration.ADVANTAGE - The method results in concentration dependent mapping in which it is easy to visually distinguish one point from another on the basis of concentration. Quantitative concentration data can be extracted from results of cluster analysis, since the distance between points are proportional to concentration, it is possible to apply an appropriate mathematical model (such as polynomial fit) to the data in order to interpolate or extrapolate unknown patterns and thereby extract concentrations.