Pyrolysis mass spectrometer for direct sampling of primary products of thermolysis reactions

A pyrolysis mass spectrometer is described which allows direct sampling into the ion source of pyrolysis products generated under collision-free conditions. Scan rates up to 20,000 amu/s allow the mass spectra to be obtained for small sample sizes (∼2 μg) and for selected time intervals (100–200 ms) during the pyrolysis experiment. A liquid nitrogen shield surrounding an open source minimizes the possiblity of reactive encounters with the source and other molecular fragments, which may occur when pyrolyzing in a confined region. Some initial results for the pyrolysis of polystyrene are reported.