Analysis of thermal decomposition products arising from polyvinyl chlorideanalogs by supersonic jet/multiphoton ionization/mass spectrometry

Polyvinyl chloride (PVC) and chlorinated polyvinyl chloride (CPVC) were the rmally decomposed at 200-500 degrees C, and the reaction products measured by supersonic jet/multiphoton ionization/mass spectrometry. No precursor mo lecules of dioxins, such as chlorobenzene, were observed from PVC, although benzene was produced as one of the major components. On the other hand, a large peak corresponding to chlorobenzene was observed, when CPVC was used as a sample. These results suggest that the release of hydrogen chloride an d aromatic ring formation occur efficiently and produce chlorinated aromati c hydrocarbons only when excess chlorine atoms are present in the chain of PVC. This method, which has very high selectivity is preferred for trace an alysis of specific compounds such as dioxin precursors in a complex mixture . Isomer-selective analysis, e.g. detection of o-, m-, and p-dichlorobenzen es, is also demonstrated in this study. (C) 2000 Elsevier Science B.V. All rights reserved.