Selective detection of (E)-hexenal in the sub-ppm range and of ethanol in the low-ppm-range using semiconducting gas sensors with temperature cycled operation

摘要

We use gas sensors with temperature cycled operation (TCO) for the detection of (E)-hexenal in the concentration range of 0.4 to 2.0 ppm and ethanol in the concentration range 2.4 to 12 ppm. We are able to distinguish between these two reducing organic vapors in the ppm range and even to quantify (E)-hexenal under any ethanol presence in this range. This was achieved by calculating linear discriminant functions from the sensor reaction pattern to a stationary gas mixture flow. The obtained LDA-coefficients, subsequently applied to the same feature set obtained at another time, can classify the gas mixture with respect to these components in the mentioned concentration range. The temperature profile during cycling operation was selected due to our prior experience with the used sensor types.