T‐Jump/time‐of‐flight mass spectrometry for time‐resolved analysis of energetic materials

Abstract

We describe a new T-Jump/time-of-flight (TOF) mass spectrometer for the time-resolved 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(5) K/s). The T-Jump probe is inserted within 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 could also be obtained and correlated to the mass spectra. As examples, we present time-resolved spectra for the ignition of nitrocellulose and RDX. The fidelity of the instrument is demonstrated in the spectra presented which show the temporal formation and decay of several species in both systems. The simultaneous measurement of temperature enables us to extract the ignition temperature and the characteristic reaction time. The time-resolved mass spectra obtained show that these solid energetic material reactions, under a rapid heating rate, can occur on a time scale of milliseconds or less. While the data sampling rate of 10,000 Hz was used in the present experiments, the instrument is capable of a maximum scanning rate of up to approximately 30 kHz. The capability of high-speed time-resolved measurements offers an additional analytical tool for the characterization of the decomposition, ignition, and combustion of energetic materials.