Development and use of a thermal desorption unit and proton transfer reaction mass spectrometry for trace explosive detection: determination of the instrumental limits of detection and an investigation of memory effects

Research output: Contribution to journalArticlepeer-review


Colleges, School and Institutes


A novel thermal desorption unit (TDU) has been developed and specifically designed for the detection of trace quantities of explosives using a proton transfer reaction mass spectrometer (PTR-MS). For the first time details on recovery times and instrumental limits of detection for the screening of explosives with this TDU/PTR-MS system are reported. We demonstrate that traces (nanograms or less) of explosives deposited on swabs are desorbed within less than a second upon insertion into the TDU. For a short period of time (seconds) a concentration “pulse” of an explosive enters the drift (reaction) tube of the PTR-MS. This temporal concentration pulse of material is monitored in real-time by recoding the product ion intensities for a given explosive as a function of time. By changing the reduced electric field in the drift tube region of the PTR-MS, we demonstrate how selectivity can be improved. This study demonstrates that the TDU/PTR-MS instrument meets security application criteria in terms of sensitivity, selectivity and recovery times.


Original languageEnglish
Pages (from-to)13-18
JournalInternational Journal of Mass Spectrometry
Early online date11 May 2015
Publication statusPublished - 15 Jun 2015


  • Proton transfer reaction mass spectrometry (PTR-MS), Explosives, Explosives detection, Thermal desorption unit