Mass spectrometry with a time resolution of a few milliseconds using a helium flushed probe system

At pressures higher than approximately 5 mbar it is nowadays common practic e to use a two-stage pressure reduction set-up, consisting of a capillary t ube as a first pressure reduction stage and an orifice as a second pressure reduction stage. We have recently demonstrated, that by using a specially constructed helium flushed probe system, a quick transport of species extra cted from a process gas to a quadrupole mass spectrometer can be achieved. In order to achieve an improved time resolution a careful redesign of the p robe and mass spectrometer system has been performed. An experimental inves tigation using a very fast chemical decomposition process revealed a time r esolution of a few milliseconds. (C) 2001 Elsevier Science Ltd. All rights reserved.