APPLICATION OF QUADRUPOLE MASS-SPECTROMETER FOR THE ANALYSIS OF NEAR-SURFACE GAS-COMPOSITION DURING DC SENSOR-TESTS

This work deals with the results obtained by a new, fully computer con trolled, complex experimental set-up planned and built at the Departme nt of Atomic Physics, TU Budapest, offering the possibility to measure the resistance of high temperature chemical sensors together with the simultaneous compositional analysis of the near sample gas region. Th e apparatus consists of a special flow-type quartz microreactor, coupl ed to a quadrupole mass spectrometer through a capillary. The applied constant voltage resistance measurement method minimises the sensor po larisation due to the measuring current. As model reactions the oxidat ion of several reducing gases like ethanol and acetone was chosen in t he 25 to 900 degrees C temperature range using the sputtered thin laye r SrTiO3 sensor. The chemical reactions are compared and discussed usi ng both self- and oven-heating. (C) 1998 Elsevier Science Ltd. All rig hts reserved.