T-Jump/Time-of-Flight Mass Spectrometery for Time Resolved Analysis of Fast Condensed Stated Reactions

Abstract

We describe a new T-jump/time-of-flight mass spectrometer for timeresolved analysis of rapid pyrolysis chemistry of solids and liquids, with a focus on energetic materials. The instrument employs a thin wire substrate which can be coated with the material of interest, and can be rapidly heated (~10 6 K/s). The T-Jump probe is inserted with the extraction region of a linear-TOF mass spectrometer, which enables multiple spectra to be obtained during a single reaction event. By monitoring the electrical characteristics of the heated wire, the temperature can also be obtained and correlated to the mass-spectra. As an example, we present time-resolved spectra for the ignition of RDX and nanocomposite thermites. The fidelity of the instrument is demonstrated in the spectra presented which show the temporal formation and decay of several species in both systems. A simultaneous measurement of temperature enables us to extract the ignition temperature and the characteristic reaction time. The obtained time resolved mass spectra show that these solid energetic material reactions, under a rapid heating rate, can occur on a time scale of milliseconds or less. The capability of high speed time resolved measurements offers an additional analytical tool for characterization of the decomposition, ignition, and combustion of energetic materials