Detecting poisoning of metal oxide gas sensors at an early stage by temperature cycled operation

摘要

In this paper we study the effect of HMDSO (hexamethyldisiloxane) on an SnO_2 metal oxide gas sensor in temperature cycled operation (TCO). Using TCO, the sensor discriminates between pure air, carbon monoxide and ethanol, both in the range of 1 ppm to 5 ppm. We could show that gas identification is still possible after poisoning with 340 ppm*min HMDSO, i.e. a HMDSO poisoning dose that fulfills the requirement of DIN EN 50194-1. Moreover, the poisoning dose can be quantified with a resolution of ±85 ppm*min again using data recorded in TCO mode, providing an easy method for early detection of HMDSO poisoning and a novel approach for sensor self-monitoring.