Qualitative and quantitative characterization of living bacteria by dynamic response parameters of gas sensor array

Dynamic response of an array of metal oxide gas sensors to volatile products of wound infectious agents is experimentally studied. The transients of the response are generated by abrupt exposure of the sensors to the headspace air of the culture with single type of bacteria. The kinetics of each sensor response is described by a limited number of specific parameters used as a set of the sensor outputs. It is experimentally demonstrated that the outputs of the two types, namely the time constants and the weight coefficients, closely correlate with the properties of volatile products of living bacteria and are related to the amount and the type of bacteria by individual proportions. Theoretical aspects of description of the amount and the type of living bacteria by individual sub-sets of the same database of the outputs are analyzed. Principles that allow a gas sensor based system to identify the wound contamination type (qualitative characteristics) and the stage of the infection (quantitative characteristics) by the dynamic response analysis are discussed.