Repetitive pulsed sampling interface for combined thermogravimetry mass spectrometry

A pneumatic sampling switch which can be adapted to the outlet of a thermog ravimetric analyzer furnace with a horizontal purge gas flow was developed. This system allows a repetitive introduction of shea sampling pulses of th ermogravimetric analyzer evolved gases to a quadrupole mass spectrometric d etector. System performance was evaluated through measuring the level of re peatability under different operation conditions. In addition, pulsed sampl ing thermogravimetry/mass spectrometry introduced no measurable quantitativ e or qualitative errors. This system can be used for monitoring thermooxida tive decomposition reactions, without accelerating the deterioration of qua drupole mass spectrometric detector performance. Furthermore, it can be use d as an inlet system for a future on-line TG/GC/MS system. (C) 1999 Elsevie r Science B.V. All rights reserved.