Study of sulfur oxidation products by pyrolysis high-resolution mass spectrometry

High-temperature oxidations of hydrogen sulfide and methanethiol with O-2 and NO2 were investigated using a special now probe that was coupled to the ion-source housing of a high-resolution mass spectrometer. The direct coupling permitted prompt analysis of oxidation products effusing from the flow probe. Nominally isobaric S-32-O-16(2) doublets were resolved at a mass resolution of >8,000, which allowed for identification of several reaction products, Under conditions of medium-low pressure (0.8-4 Torr) and long mean residence times (0.5 s) in the probe, the oxidations yielded mostly stable products. Hydrogen sulfide was oxidized to form SO, SO2, S-2 and S2O whose relative intensities were studied as a function of temperature and reactant mixture composition, Methanethiol yielded CH3SNO, CH3SSCH3, CS2, SO2 and traces of SO3 and SO3H depending on the temperature and reactant mixture composition,