Manage the Selectivity of the Analysis

In the traditional analyzers of the total concentration of combustible gases (a mixture of concentrations of combustible gases), the dependence of the signal value for each component of the mixture is determined by from their concentrations. This signal should be enclosed in the range from 0.5% LEL to 50% of the LEL. The calibration of this analyzer is carried out on some gas that lies within the this range. Usually methane or propane is used for this purpose [1,2]. In the article the possibility of controlling the selectivity of the analysis of gas components by the methods of negative filtration [3] of the useful signal in the optical path of the gas analyzer is considered. There are many analytical tasks for which it is necessary to achieve the same sensitivity to the measured gas components. For example, in the analyzer mentioned above, the total concentration of combustible gases in the air. Indeed, different combustible gases can lead to similar effects and it is not possible to determine the concentration of each. The most common are flammable gases such as methane, butane, propane. Of course, it is desirable that the combustion gas alarm has the same sensitivity to these gases and does not respond to interfering, such as CO2.